For many decades, standard dietary advice in the United States has been to eat a diet rich in vegetable sources of protein and selected lipids (oils), while avoiding beef and other sources of animal proteins and fats (technically the type of fats known as lipids).
New studies are showing that this advice may be wrong, and may have led to the rise in obesity and obesity-related disorders over this same period.
In this article, I review the basis for the previously-standard advice, the available new data, and the conclusions that may be considered based on these new data.
The audience for this review is the intelligent layman who wishes to understand the issues better. For this reader, citations to the primary and secondary literature are provided to facilitate further reading.
Constructive comments and questions may be directed to review-article at leafycreekfarm.com.
This article is long so details are hidden until you click on the text "click to show details" wherever more detail is available. Or, you can
Setting the Stage (the short version)
The short story is that after World War II, the leading cause of death in the United States of America was coronary artery disease causing heart attacks. No one knew why it was happening, and the problem was getting worse. A great effort was made to find out why. Over the next decades, research studies identified the risk factors we know today: male sex, increasing age, use of cigarettes, high blood pressure, diabetes, and high cholesterol. Of the risk factors that could be changed, further effort was made to find out whether changing them made any difference.
It was found that stopping use of cigarettes; and normalizing the blood pressure, blood sugar in type I and type II diabetes, and cholesterol, did lower the rate at which coronary artery disease and heart attacks developed. These measures have worked so well that standardized guidelines have been developed and are periodically refined for blood pressure, blood sugar, and cholesterol. By and large, these guidelines are controversial only in their details; the overall theory and practice for each seems pretty solidly understood. [It should be noted that controversy exists (e.g. here) regarding drug treatment of cholesterol because of distrust of pharmaceutical companies.]
Unfortunately, even though the studies of diet and cholesterol began in the same time period, the theory and practice of dietary control of cholesterol is not well understood, and what is thought to be true now appears to be changing.
Setting the Stage (the longer version)
The reasons for the transition from the decades-old emphasis on plant sources of food to emphasis on animal sources are complex but start with the fact that studies of diet are very hard to do. After all, people tend to eat what they want and a lot of studies just ask people what they ate. By contrast, for treatment of blood pressure, blood sugar, and cholesterol with medications, people just have to take the medications.
Worse, the studies of diet and heart disease began just after the chaos of World War II and the rebuilding afterward. The majority of the scientists who worked on the problem then thought they found that eating animal protein was associated with more heart attacks than eating plant protein. They were so sure of this, despite protests from other scientists working on the same problem at the time, that this concept became accepted as Truth and became the basis of official dietary recommendations that have persisted for decades. Only recently have the original data been reexamined and found to be not as certain as was once thought. This is discussed in more detail below.
Pertinent to this article, in particular, the original studies lumped together both processed meat such as salami and unprocessed meat such as raw beef and chicken. Newer studies show that processed meats are indeed not healthy, but that unprocessed meats not only are healthy but actually seem to be healthier than purely plant-based protein sources as measured by the effects on blood pressure, blood sugar (glucose), and blood cholesterol.
Relationship between cholesterol and coronary atherosclerosis
The reason we think there is a relationship between cholesterol and blockages in the arteries to the heart (coronary atherosclerosis) is that many studies, done as carefully as possible, have found that people who have high cholesterol levels are more likely to develop atherosclerosis. This is just an association and does not prove a causal relationship. However, when the level of cholesterol is reduced one way or another, the risk of developing atherosclerosis is also lowered. This proves causality (unless the methods used to reduce cholesterol by themselves reduce the risk). There are many ways to reduce cholesterol, starting with a very strict low-cholesterol diet, then progressing to losing weight for the obese, and then progressing to various medications. No single method works in everyone, but the fact that there are many methods suggests that the method is not the causal factor, and that lowering cholesterol is.
Relationships between diet, cholesterol, and coronary atherosclerosis
To discuss the next topic, diet and cholesterol, we have to review some history. Up until World War II was over in 1945, coronary atherosclerosis was thought to be an inevitable consequence of aging. Very little was known about its causes. For example, the standard K rations issued to soldiers in that war
included a pack of cigarettes with every ration. It was not known that diabetes and hypertension were strong risk factors. In fact, in the middle of a world war, these questions were not very important. Also, for interest, the scientist in charge of developing the K rations was Dr. Ancel Keys.
However, after the war and into the 1950s, the death rate from heart disease was found to be high and rising. The rate of death from heart disease became so high that it was considered an urgent matter of public health to find out why.
Several important projects were started:
The Framingham study, which started in 1948 and still continues, was set up to survey all inhabitants of the town of Framingham, Massachusetts in the United States of America. Every two years, all inhabitants were interviewed and underwent measurements of height, weight, blood pressure, and blood chemistries, as well as electrocardiography. It was this study that, over time, identified the major risk factors for development of coronary atherosclerosis: diabetes mellitus, hypertension, high cholesterol, cigarette smoking, male sex, advancing age, and family history of premature heart disease.
The "Seven Countries" diet study. This was a very carefully done study of the diet in seven countries, designed shortly after World War II, for which the rates of atherosclerotic heart disease were known. It is the origin of the so-called "Mediterranean diet" that came to be associated with lower risk of coronary atherosclerosis. The scientist who spearheaded this study, Ancel Keys, was reportedly a very charismatic figure who dominated the popular press and scientific establishment during his lifetime. Please see the notes above on his role in developing K rations with cigarettes during World War II.
In brief, this study was felt to have proven that diets low in animal protein and high in fish and plant sources of protein, were associated with lower risk of heart disease. Technically, this was a prospective cohort study from which a link was suggested between saturated fat and coronary atherosclerosis. This apparent conclusion formed the basis for dietary recommendations starting in the 1960s(?) and continuing to the present day. To be fair, Dr. Keys may not have been the person who inferred the conclusion of causality but there is no question that this inference was made at the time and was the basis for current dietary recommendations regarding dietary intake of fats.
The reason for looking back and questioning the conclusions of the study were that, in retrospect, it had a number of very serious flaws.
For example, included only seven countries (United States of America, Italy, Finland, Greece, the Netherlands, Japan, and Yugoslavia (now Croatia and Serbia), and these were not selected at random. Were they selected to reach a pre-determined conclusion? The study did not include a number of countries such as Denmark, France, Norway, and Switzerland, where the rate of atherosclerotic heart disease was low (mortality 200-300 per 100,000) but the diet was high in animal protein, and Chile, where the diet is Mediterranean-like and and age-specific mortality from cardiovascular disease was 407 per 100,000 in 1960(*). The important survey in Greece, which has a population that was strongly observant of Catholic holidays, was performed during Lent. This is notable because meat is not eaten during Lent, yet the population is certainly free to eat meat during much of the remainder of the year.
(*Please note that the figures given are raw data, not adjusted for other risk factors for smoking, hypertension, access to health care, and many other factors. The best one can hope for with the available data is a fuzzy picture of possible relationships, and certainly not exact patterns. This uncertainty, of course, confuses the picture on both sides of the argument.)
How could this have happened? It is tempting to blame Dr. Keys, and many have done so (here, for example). However, a group of his colleagues issued a persuasive paper in his defense in 2017. They pointed out that the conveniences we take for granted today were simply not available when this study was done. Inexpensive communication was not available. Much of the civilized world was still recovering from the War. Additional countries could not have been included because each included country was required to pay for its own expenses, and many countries simply could not or would not do so. In some countries, such as the Netherlands, the diet during the War was at the near-starvation level from 1940 to 1944, so measurement of post-War diet in the 1950s would not account for the death rate in 1950-1952. The paper goes on to examine each of the criticisms and to refute them with respect to the question of intention. The reader is encouraged to read this paper carefully.
As noted in the discussion of this paper, the principal conclusion of this study was that heart disease was preventable with lifestyle and not an inevitable consequence of aging, as had been thought; and that dietary intake of saturated fat should be reduced and replaced with mainly plants and seafood.
So what is the current importance of the Seven Country Study? Three important metanalyses have been published recently. One showed only weak support and two showed no support for the hypothesis that animal-derived saturated fatty acids increase the risk of coronary artery disease.
A metanalysis published in 2014 concluded that "Current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats."
Another metanalysis published in 2014 concluded "The findings of this updated review are suggestive of a small but potentially important reduction in cardiovascular risk on reduction of saturated fat intake. Replacing the energy from saturated fat with polyunsaturated fat appears to be a useful strategy, and replacement with carbohydrate appears less useful, but effects of replacement with monounsaturated fat were unclear due to inclusion of only one small trial. This effect did not appear to alter by study duration, sex or baseline level of cardiovascular risk. Lifestyle advice to all those at risk of cardiovascular disease and to lower risk population groups should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturated fats. The ideal type of unsaturated fat is unclear."
published in 2015 found, "Saturated fats are not associated with all cause
mortality, CVD [cardiovascular disease], CHD [coronary heart disease],
ischemic stroke, or type 2 diabetes, but the evidence is heterogeneous with
methodological limitations. Trans fats are associated with all cause
mortality, total CHD, and CHD mortality, probably because of higher levels
of intake of industrial trans fats than ruminant trans fats. Dietary
guidelines must carefully consider the health effects of recommendations
for alternative macronutrients to replace trans fats and saturated fats.
In other words, the original conclusions of this study are not valid given subsequent studies: saturated fats, which are found predominantly in animal protein, have not proven to be a strong cause of coronary atherosclerosis.
In more detail, one study found a weak association between cardiovascular risk and intake of saturated fat while two studies found none. One of these two studies found that trans fats were associated with death from all causes (all cause mortality), death from coronary heart disease (CHD mortality), and total coronary heart disease (total CHD), but that industrial trans fats (such as margarine) were more likely responsible than fats from ruminants (such as beef).
Let us shift gears for a moment to discuss the irony that margarine was
formerly promoted as heart-healthy because it is derived from vegetable fat
and not animal fat; only subsequent study showed that it appears to be
worse for us than animal fat.
In fact, according to the wikipedia article on
trans fats, "As early as 1956, there were suggestions in the scientific
literature that trans fats could be a cause of the large increase in
coronary artery disease but after three decades the concerns were still
largely unaddressed. Instead, by the 1980s, fats of animal origin had
become one of the greatest concerns of dieticians. Activists, such as Phil
Sokolof, who took out full page ads in major newspapers, attacked the use
of beef tallow in McDonald's french fries and urged fast-food companies to
switch to vegetable oils. The result was an almost overnight switch by most
fast-food outlets to trans fats. Studies in the early 1990s, however,
brought renewed scrutiny and confirmation of the negative health impact of
trans fats. In 1994, it was estimated that trans fats caused 20,000 deaths
annually in the United States from heart disease. Mandatory food labeling
for trans fats was introduced in several countries. Campaigns were
launched by activists to bring attention to the issue and change the
practices of food manufacturers. In January 2007, faced with the
prospect of an outright ban on the sale of their product, Crisco was
reformulated to meet the United States Food and Drug Administration (FDA)
definition of 'zero grams trans fats per serving'...." This is a tale of
caution to those who would advocate for changing the public's dietary
habits without having the full scientific picture, a picture which simply
may not be available in a given year or decade, or which may available only to those
who are willing to read the entire scientific literature instead of the the "consensus" literature
on the given subject.
Returning to the primary theme, the conclusion that saturated fat and in particular ruminant animal fat may not be associated with coronary artery disease is almost revolutionary given the primary importance attributed to the Seven Country Study and its conclusion over more than 60 years ago that saturated fats are "bad".
Of course, this conclusion is controversial and more clinical studies (rather than metanalyses) are necessary before the "saturated fat" paradigm can be considered obsolete. And, for the observant, this conclusion comes from only metanalyses, a method that has weaknesses discussed below.
As a shameless plug, we would note that at least one pundit has recommended organic grass-fed pastured beef as part of a healthy diet! (Honesty compels us to add that that author gave no specific justification for his recommendation.)
In the discussion below, we will focus on the relationship between either measured clinical outcomes or measured changes in biochemical markers that are clearly linked with the risks of bad clinical outcomes.
Why do we need cholesterol anyway?
We are all made of cells, and the outer walls (membranes) of all of our cells are made of ... cholesterol! We cannot live without it. In fact, if we eat less of it, our livers make more.
What's with all the different types of cholesterol? Good? Bad? Give me a break!
So, is there just one kind of cholesterol? Well, the part that is in the cells is the same. But hang onto your hat... When we talk about "cholesterol", we are usually referring to a combination of that molecule piggy-backed (or attached, if you will) to a carrier molecule that takes the cholesterol molecule from place to place in the body. The reason for this is that cholesterol, being a fat, does not mix well with blood, which is mostly water. The carrier molecule has a part that the cholesterol can stick to and a part that mixes well with water. There are a variety of these carriers. For our purposes, we can think just of the "good" cholesterol (cholesterol combined with "high density lipoprotein" or "HDL") and the "bad" cholesterol (cholesterol combined with "low density lipoprotein" or "LDL"). Each of these comes in several forms and there are other forms also. Additionally, the "bad" cholesterol can be small and dense, like a golf ball, or big and fluffy, sort of like a tennis ball. The small dense kind is worse than the big fluffy kind.
To summarize, we have "good" cholesterol and "bad" cholesterol, by which we refer to the same cholesterol in cell membranes when it is combined with HDL or LDL. These combinations are called lipoproteins. The "good" HDL is returned to the liver for its cholesterol to be broken down into other molecules. The "bad" LDL travels out to the tissue to deliver cholesterol where it is needed and, as a side effect, to accumulate in the walls of blood vessels which narrows them and clogs them up.
The reason this distinction is important is that we know from many studies that people with high levels of LDL have more heart attacks, those with high HDL have fewer, and treatments that lower the LDL do reduce the frequency of heart attacks and other complications of high cholesterol.
Because there is controversy related to distrust of the pharmaceutical industry, it is helpful to consider the extreme case of familial hypercholesterolemia because it is so awful that studies in that disorder are very unlikely to have been distorted by whatever malfeasors may exist:
Thus, having a high LDL level is associated with an increased risk of coronary heart disease, higher levels are associated with greater risk, and lowering the LDL level even by mechanical means (apheresis) lowers the risk of coronary heart disease. We can accept therefore with good confidence that LDL is a treatable cause of coronary heart disease, and that lowering elevated levels by whatever means is a good thing to do.
Why are there so many types of clinical studies?
There are lots of types of studies. Some studies keep people locked up in rooms where everything they eat is monitored while others rely on people to eat only what they are given. Both of these types of studies are not common. When studies have tens of thousands of people being studied, they are often asked what they eat and whatever they answer is what goes into the study. This method is much less expensive but obviously not nearly as reliable.
Some studies keep going for years to see how long people live and what kinds of diseases they get along the way. These are very expensive and, of course, take years to do. Some are short term and rely on blood tests for "surrogate" endpoints, such as changes in blood pressure, HDL, LDL, etc.
For example, a group of people may have their blood chemistries measured at the start of a study. Then, they are divided randomly into two or more subgroups, and each subgroup is asked to eat a specific diet for a period of time, and then the measurements are repeated. In a cross-over study, all of the subjects then resume their normal diets for another period of time, then repeat the process but with the diet that had been assigned to the other (or another) subgroup. In this way, each individual acts as his or her own control. During such a study, which can be done in just a few months with a few dozen or a few hundred people, much valuable information can be gained about the surrogate endpoints. To do a similar study that measured heart attack rates, for example, would take many years and tens of thousands of subjects.
In the discussion below, you will see results based on mortality and morbidity (that is, death and serious illness) when they are available. Most of the time, though, you will see results based on the effect of diet on risk factors such as blood pressure, tendency toward developing diabetes, and lipoprotein levels (HDL and LDL).
The obesity epidemic, or So what is wrong with not eating meat?
The term "obesity epidemic" refers to the observation that the population in the United States of America and world-wide began to become obese in the late 1970's to early 1980's. This occurred after vigorous public health efforts began in the 1960's to convince people to abandon meat and substitute plant sources of protein.
However, studies here, here, and here have suggested that there are two causes for this: the amount of calories for a given amount of protein is much greater in plant sources of protein compared with animal sources of protein, so fewer calories are needed to meet protein requirements; and eating animal fat causes us to feel full more quickly so we eat less food that contains it. Diets with large components of animal protein are called Paleo or hunter-gatherer diets. A review of studies showed improvement in blood sugar and weight in Australian Aborigines who were diabetic when their diet returned to a hunter–gatherer lifestyle for 7 weeks. Similar findings were observed in Sweden, with improvement not only in blood sugar and weight but also in blood pressure and HDL levels.
There may be other contributors to the obesity epidemic. Some authors also feel that the abundance of cheap, plentiful food combined with modern technology that reduces the need for physical exertion have led to people simply eating too much. And, there are a number of chemicals that may be related to increased appetite, so-called "obesogens", including high-fructose corn syrup, caffeine, certain components of plastic used to hold food, pesticides found in food, and pharmaceutical drugs. For the purposes of this article, we will focus on the possible contributions of eating plant protein to the exclusion of animal protein.
The problem with obesity is that it causes a number of health problems that can be reversed if the excess weight is lost: diabetes mellitus, hypertension, elevated cholesterol, sleep apnea, and fatty liver disease. It has also been associated with certain cancers and with cognitive dysfunction. And, of course, the risk of heart attack goes up rapidly when one develops diabetes mellitus, hypertension, and elevated cholesterol.
We have now set the stage for a discussion of the risks and benefits of eating lean, unprocessed meat such as grass-fed cattle. We have seen that diet is only one part of optimizing the reader's cardiovascular risk profile, that the dictum that "beef is bad for you" is no longer acceptable scientifically, and that there may be advantages to eating a lot of meat if you are overweight and/or have diabetes. (Of course, any medical questions must be discussed with your own physician before you act on anything you read or do not read here.)
We have also seen that we have to use "surrogate endpoints" like LDL levels, blood pressure, and blood sugar responses to experimental changes in diet because we simply do not have, and are not likely to get soon, sufficiently large randomized clinical trials of various types of diet with endpoints like total mortality.
From DGA page
83: "USDA Food Patterns: Healthy Mediterranean-Style Eating Pattern":
" The Healthy Mediterranean-Style Pattern is adapted from the Healthy
U.S.-Style Pattern, modifying amounts recommended from some food groups to
more closely reflect eating patterns that have been associated with
positive health outcomes in studies of Mediterranean-Style diets... The Healthy
Mediterranean-Style Pattern contains more fruits and seafood and less dairy
than does the Healthy U.S.-Style Pattern."
The key statement in this official description is:
The Healthy Mediterranean-Style Pattern is considered a good diet, so that any diet that is better than this diet is worth considering.
(This is important because we are about to discuss new studies showing that eating more lean meat gives better results than this diet.)
What is meant by "meat", and what is the difference between processed and unprocessed meat?
"Meat, also known as red meat, includes all forms
of beef, pork, lamb, veal, goat, and non-bird game (e.g., venison, bison,
and elk). Poultry includes all forms of chicken, turkey, duck, geese,
guineas, and game birds (e.g., quail and pheasant)."
"Meats and poultry vary in fat content and include both fresh and processed forms."
"Lean meats and poultry contain less than 10 g of fat, 4.5 g or less of
saturated fats, and less than 95 mg of cholesterol per 100 g and per
labeled serving size (e.g., 95% lean ground beef, pork tenderloin, and
skinless chicken or turkey breast)."
"Processed meats and processed poultry (e.g., sausages, luncheon meats,
bacon, and beef jerky) are products preserved by smoking, curing, salting,
and/or the addition of chemical preservatives."
Is processed meat good or bad for your heart health?
From the DGA, page 25: "About Meats & Poultry": "Strong evidence from
mostly prospective cohort studies but also randomized controlled trials has
shown that eating patterns that include lower intake of meats as well as
processed meats and processed poultry are associated with reduced risk of
CVD in adults. Moderate evidence indicates that these eating patterns are
associated with reduced risk of obesity, type 2 diabetes, and some types of
cancer in adults. As described earlier, eating patterns consist of
multiple, interacting food components, and the relationships to health
exist for the overall eating pattern, not necessarily to an isolated aspect
of the diet. Much of this research on eating patterns has grouped together
all meats and poultry, regardless of fat content or processing, though some
evidence has identified lean meats and lean poultry in healthy eating
The key statements in this official advice are:
The available studies lumped together lean meat with processed meat,
Processed meat is certainly unhealthy, and
Lean meat looks like it might be healthy but we do not have the studies yet that let us say so.
From DGA page 57: "About Meats & Poultry":
"Because solid fats are the major source of saturated fats, the strategies for reducing the intake of solid fats parallel the recommendations for reducing saturated fats. These strategies include choosing packaged foods lower in saturated fats; shifting from using solid fats to oils in preparing foods; choosing dressings and spreads that are made from oils rather than solid fats; reducing overall intake of solid fats by choosing lean or low-fat versions of meats, poultry, and dairy products; and consuming smaller portions of foods higher in solid fats or consuming them less often."
The key statements in this official advice are:
Solid fats, which are often saturated fats, appear to be unhealthy.
Among the methods for eating less solid fats is to choose lean or low-fat versions of meats, poultry, and dairy products.
It is important to know something about the substances added to processed meat in the processes of "smoking, curing, salting, and/or the addition of chemical preservatives".
Salting of course means adding large quantities of salt. But what do smoking, curing, and chemical preservatives refer to?
Nitrites, nitrates, and nitrosamines. And sometimes smoke.
from 2017 of the hazards of eating red meat comments in detail on the
various compounds that are found in both processed and unprocessed meats,
and how these are transformed in the cooking process.
Summarizes numerous studies that examined the relative risk of both types
of meat on development of diabetes mellitus, stroke, coronary artery
disease, various cancers, and total mortality. Of note, the summaries do
not comment on how confounding variables such as smoking and other
unhealthy lifestyles may have differed between the subgroups compared in
Interestingly, the author reveals a bias against consumption of red
meat in the Conclusion of the study, "Moreover, the production of red meat
also involves an environmental burden. Therefore, some European countries
have already integrated these two issues, human health and the ‘health of
the planet’, into new national dietary guidelines and recommended limiting
the consumption of red meat."
The reader may be interested in a companion article
on this website that reviews the evidence favoring the conclusion that
cattle grazed using the "adaptive multipaddock" method lead to a net
reduction, not an increase, in greenhouse gases because the grass and its soil, when
properly grazed, sequester an enormous amount of carbon dioxide and also more
rapidly metabolize methane into inert compounds.
page 7, on coronary heart disease:
"The current evidence suggests that high consumption of red meat, both
unprocessed and processed, may increase the risk of CHD. However, in a
recent dose–response meta-analysis of three prospective cohorts and one
case–control study including 56 311 participants and 769 incident events,
no association was found between the consumption of unprocessed red meat
and CHD risk (RR summary 1.00, 95% CI 0.81–1.23 per 100 g serving/day)
. Following this meta-analysis, which was limited by the low number of
events, results from the Nurses’ Health Study (including 84 136 women and
2210 incident non-fatal myocardial infarctions and 952 deaths due to CHD)
showed a statistically significantly increased CHD risk (RR 1.19, 95% CI
1.07–1.32 per serving of unprocessed red meat/day) . Nevertheless,
this finding needs to be confirmed in other populations." [emphasis added]
also on page 7, also regarding coronary heart disease:
"The evaluation of processed meat consumption and incident CHD in a
dose–response meta-analysis based on six studies including 614 062
participants and 21 308 events  indicated that each 50 g serving/day
of processed meat was associated with a 42% higher risk of CHD (RR summary
1.42, 95% CI 1.07–1.89). In the analysis restricted to prospective studies,
the risk was 44% (7–95%) higher." [emphasis added]
page 8, on cancer:
"In October 2015, a Working Group of 22 scientists from 10
countries met at the International Agency for Research on Cancer (IARC) in
Lyon, France, to evaluate the carcinogenicity of the consumption of red and
processed meat . They assessed more than 800 epidemiological studies
that investigated cancer associations with the consumption of red meat or
processed meat in many countries with diverse diets and
races/ethnicities. The Working Group concluded, based on the large amount
of data and the consistency of the associations across studies in different
populations, that there is ‘sufficient evidence in humans for the
carcinogenicity of the consumption of processed meat’. Concerning red
meat, chance, bias and confounding could not be ruled out with the same
degree of confidence as applied to processed meat, as no clear association
was observed in several of the large cohort studies. The conclusion of the
Working Group was that there is ‘limited evidence in humans for the
carcinogenicity of the consumption of red meat’"
In other words, processed meat is likely carcinogenic but there is not sufficient evidence to assert the same with respect to unprocessed meat. [emphasis added]
page 11, on total mortality: "Interestingly, in an early meta-analysis
of five prospective studies from Western countries, mortality was 16–18%
lower amongst occasional meat eaters, vegetarians and fish eaters, whilst
regular meat eaters and vegans shared the highest mortality."
also page 11, also on total mortality. "Most of the accumulated
evidence from observational epidemiological studies is for all-cause
mortality. The summary risk estimates in a recent meta-analysis of nine
prospective cohorts evaluating mortality risk in relation to the
consumption of unprocessed red meat and processed meat are based on data
from 1 330 352 participants from the USA (five cohorts), Europe (three
cohorts) and China (one cohort), including 137 376 all-cause deaths
. Processed meat consumption was statistically significantly associated
with increased risk (RR summary 1.23, 95% CI 1.17–1.28 for the highest
versus the lowest category of consumption). In a dose–response
meta-analysis, the consumption of processed meat was significantly
positively associated with all-cause mortality in a nonlinear fashion (P
nonlinearity = 0.003); comparing processed meat consumption of 60 g day 1
vs. 10 g day 1 , a 22% increase in risk was observed (RR summary 1.22, 95%
CI 1.13–1.31)." [emphasis added]
"High unprocessed red meat consumption was not significantly associated
with the increased all-cause mortality (RR summary 1.10, 95% CI 0.98–1.22
for the highest versus the lowest category of consumption)...." [emphasis added]
Thus, when processed and unprocessed meats are studied separately, the first
seems not to be very healthy while the second is either not unhealthy or is only mildly so.
And another review article is more clear that the problem is with processed meats, not red (unprocessed) meats:
"Consumption of processed meats, but not red meats, is associated with
higher incidence of CHD and diabetes mellitus. These results highlight the
need for better understanding of potential mechanisms of effects and for
particular focus on processed meats for dietary and policy
Is unprocessed meat good or bad for your heart health?
From DGA page 25: "About Meats & Poultry":
"In separate analyses, food pattern modeling has
demonstrated that lean meats and lean poultry can contribute important
nutrients within limits for sodium, calories from saturated fats and added
sugars, and total calories when consumed in recommended amounts in healthy
eating patterns, such as the Healthy U.S.-Style and Mediterranean-Style
Eating Patterns. The recommendation for the meats, poultry, and eggs
subgroup in the Healthy U.S.-Style Eating Pattern at the 2,000-calorie
level is 26 ounce-equivalents per week. This is the same as the amount that
was in the primary USDA Food Patterns of the 2010 Dietary Guidelines. As
discussed in Chapter 2, average intakes of meats, poultry, and eggs for
teen boys and adult men are above recommendations in the Healthy U.S.-Style
Eating Pattern. For those who eat animal products, the recommendation for
the protein foods subgroup of meats, poultry, and eggs can be met by
consuming a variety of lean meats, lean poultry, and eggs. Choices within
these eating patterns may include processed meats and processed poultry as
long as the resulting eating pattern is within limits for sodium, calories
from saturated fats and added sugars, and total calories."
The key statement in this official advice is:
In a healthy diet, a variety of lean meats, lean poultry, and eggs can be sources for some of the protein.
discussed in the previous section presented data showing that unprocessed meat is either not a health risk or is only mildly so. Please note the bias revealed by the author against consumption of red meat in the Conclusions of that article. Please press the "click to show details" link to display it.
Now, at last, we get to the new experimental data comparing the
standard Mediterranean-Style diet to modifications including addition of
more protein and especially of lean unprocessed meat.
"Limited consumption of red meat, including beef, is one of many
often-suggested strategies to reduce the risk of coronary heart disease
(CHD). However, the role that beef consumption specifically plays in
promoting adverse changes in the cardiovascular risk factor profile is
unclear. A meta-analysis of randomized, controlled, clinical trials (RCTs)
was conducted to evaluate the effects of beef, independent of other red and
processed meats, compared with poultry and/or fish consumption, on
lipoprotein lipids. RCTs published from 1950 to 2010 were considered for
inclusion. Studies were included if they reported fasting lipoprotein lipid
changes after beef and poultry/fish consumption by subjects free of chronic
disease. A total of 124 RCTs were identified, and 8 studies involving 406
subjects met the prespecified entry criteria and were included in the
analysis. Relative to the baseline diet, mean ± standard error changes (in
mg/dL) after beef versus poultry/fish consumption, respectively, were -8.1
± 2.8 vs. -6.2 ± 3.1 for total cholesterol (P = .630), -8.2 ± 4.2 vs. -8.9
± 4.4 for low-density lipoprotein cholesterol (P = .905), -2.3 ± 1.0
vs. -1.9 ± 0.8 for high-density lipoprotein cholesterol (P = .762), and
-8.1 ± 3.6 vs. -12.9 ± 4.0 mg/dL for triacylglycerols (P = .367).
Changes in the fasting lipid profile were not significantly different with beef
consumption compared with those with poultry and/or fish
consumption. Inclusion of lean beef in the diet increases the variety of
available food choices, which may improve long-term adherence with dietary
recommendations for lipid management."
In other words, the findings with beef were statistically the same as for poultry and/or fish as measured by improvement in total cholesterol, LDL and HDL cholesterol, and triglycerides. Among the 8 studies analyzed, the blood tests were compared with the measurements made while the patients were eating whatever their usual diet was.
"In an investigator-blinded, randomized, crossover, controlled feeding trial, 41 subjects [mean ± SD age: 46 ± 2 y; mean ± SD body mass index (kg/m2): 30.5 ± 0.6] were provided with a Mediterranean Pattern for two 5-wk interventions separated by 4 wk of self-selected eating. The Mediterranean Patterns contained ∼500 g [typical US intake (Med-Red)] and ∼200 g [commonly recommended intake in heart-healthy eating patterns (Med-Control)] of lean, unprocessed beef or pork per week. Red meat intake was compensated by poultry and other protein-rich foods. Baseline and postintervention outcomes included fasting blood pressure, serum lipids, lipoproteins, glucose, insulin, and ambulatory blood pressure. The presented results were adjusted for age, sex, and body mass at each time point (P < 0.05)."
"Total cholesterol decreased, but greater reductions occurred with Med-Red than with Med-Control (−0.4 ± 0.1 and −0.2 ±0.1 mmol/L, respectively, intervention × time = 0.045]. Low-density lipoprotein decreased with Med-Red but was unchanged with Med-Control [−0.3 ± 0.1 and −0.1 ± 0.1 mmol/L, respectively, intervention × time = 0.038], whereas high-density lipoprotein (HDL) concentrations decreased nondifferentially [−0.1 ± 0.0 mmol/L]. Triglycerides, total cholesterol:HDL, glucose, and insulin did not change with either Med-Red or Med-Control. All blood pressure parameters improved, except during sleep, independent of the red meat intake amount."
"In conclusion, adults who are overweight or obese can consume typical US
intake quantities of red meat (∼70 g/d) as lean and unprocessed beef and
pork when adopting a Mediterranean Pattern to improve cardiometabolic
disease risk factors. Our results support previous observational and
experimental evidence which shows that unprocessed and/or lean red meat
consumption does not increase the risk of developing cardiovascular disease
(11) or impair associated risk factors (13)."
In other words, the group that ate more red meat had better outcomes than the standard Mediterranean Pattern diet group as measured by total cholesterol and LDL. The other parameters measured did not worsen in the group that ate more red meat.
"Design, Setting, and Participants: Randomized, 3-period, crossover feeding study....
Participants were 164 adults with prehypertension or stage 1 hypertension. Each feeding
period lasted 6 weeks and body weight was kept constant."
"Interventions: A diet rich in carbohydrates; a diet rich in protein, about half from
plant sources; and a diet rich in unsaturated fat, predominantly monounsaturated fat.
Main Outcome Measures Systolic blood pressure and low-density lipoprotein
"Results: Blood pressure, low-density lipoprotein cholesterol, and estimated coronary heart
disease risk were lower on each diet compared with baseline. Compared with the car-
bohydrate diet, the protein diet further decreased mean systolic blood pressure by 1.4
mm Hg (P = .002) and by 3.5 mm Hg (P=.006) among those with hypertension and de-
creased low-density lipoprotein cholesterol by 3.3 mg/dL (0.09 mmol/L; P=.01), high-
density lipoprotein cholesterol by 1.3 mg/dL (0.03 mmol/L; P=.02), and triglycerides by
15.7 mg/dL (0.18 mmol/L; P⬍.001). Compared with the carbohydrate diet, the unsat-
urated fat diet decreased systolic blood pressure by 1.3 mm Hg (P = .005) and by 2.9
mm Hg among those with hypertension (P=.02), had no significant effect on low-
density lipoprotein cholesterol, increased high-density lipoprotein cholesterol by 1.1 mg/dL
(0.03 mmol/L; P=.03), and lowered triglycerides by 9.6 mg/dL (0.11 mmol/L; P=.02).
Compared with the carbohydrate diet, estimated 10-year coronary heart disease risk was
lower and similar on the protein and unsaturated fat diets."
"Conclusion: In the setting of a healthful diet, partial substitution of carbohydrate
with either protein or monounsaturated fat can further lower blood
pressure, improve lipid levels, and reduce estimated cardiovascular risk."
Compared with a standard healthy diet, substituting protein (half from
plants and the rest from chicken and fish, with about the same amount of
beef in all three diets) or unsaturated fat for carbohydrate actually improved blood pressure and lipid levels, and reduced estimated cardiovascular risk.
Thus, in this carefully done study, adding protein to the standard "healthy" diet actually made it more healthy.
"Results: Red meat intake did not affect lipid-lipoprotein profiles or
blood pressure values postintervention (P > 0.05) or changes over time
[weighted mean difference (95% CI): 20.01 mmol/L (20.08, 0.06 mmol/L), 0.02
mmol/L (20.05, 0.08 mmol/L), 0.03 mmol/L (20.01, 0.07 mmol/L), and 0.04
mmol/L (20.02, 0.10 mmol/L); 20.08 mm Hg (20.26, 0.11 mm Hg); and 21.0 mm
Hg (22.4, 0.78 mm Hg) and 0.1 mm Hg (21.2, 1.5 mm Hg) for TC, LDL
cholesterol, HDL cholesterol, triglycerides, TC:HDL cholesterol, SBP, and
DBP, respectively]. Among all subjects, TC, LDL cholesterol, HDL
cholesterol, TC:HDL cholesterol, triglycerides, and DBP, but not SBP,
decreased over time (P > 0.05)."
"Conclusions: The results from this
systematically searched meta-analysis of RCTs support the idea that the
consumption of ≥0.5 servings of total red meat/d [per day] does not influence blood
lipids and lipoproteins or blood pressures."
Is there a difference between unprocessed beef from animals fed grain compared with grass-fed cattle?
A physician at The Mayo Clinic opined that grass-fed beef may be better.
Healthier mix of the various types of saturated fatty acids: less myristic fatty acid and less palmitic fatty acid, and more stearic fatty acid.
More of the healthy omega-3 fatty acid, better (higher) ratio of omega-3 to omega-6 fatty acid, more omega-7 fatty acid, and more conjugated linoleic acid. All of these are polyunsaturated fatty acids. Also, more vaccenic Acid, a metabolic precursor to conjugated linoleic acid.
More healthy vitamins, anti-oxidants, and minerals.
"Research spanning three decades supports the argument that grass-fed beef (on a g/g fat basis), has a more desirable SFA lipid profile (more C18:0 cholesterol neutral SFA and less C14:0 & C16:0 cholesterol elevating SFAs) as compared to grain-fed beef. Grass-finished beef is also higher in total CLA (C18:2) isomers, TVA (C18:1 t11) and n-3 FAs on a g/g fat basis. This results in a better n-6:n-3 ratio that is preferred by the nutritional community. Grass-fed beef is also higher in precursors for Vitamin A and E and cancer fighting antioxidants such as GT and SOD activity as compared to grain-fed contemporaries.
Grass-fed beef tends to be lower in overall fat content, an important consideration for those consumers interested in decreasing overall fat consumption. Because of these differences in FA content, grass-fed beef also possesses a distinct grass flavor and unique cooking qualities that should be considered when making the transition from grain-fed beef. To maximize the favorable lipid profile and to guarantee the elevated antioxidant content, animals should be finished on 100% grass or pasture-based diets.
Grain-fed beef consumers may achieve similar intakes of both n-3 and CLA through consumption of higher fat portions with higher overall palatability scores. A number of clinical studies have shown that today's lean beef, regardless of feeding strategy, can be used interchangeably with fish or skinless chicken to reduce serum cholesterol levels in hypercholesterolemic patients."
Is there an advantage to Animal Welfare Approved meat? What does that mean, anyway?
We believe that all living creatures should be treated as kindly as
possible. Nature when seen up close is not always pretty:
larger fish swallow smaller fish alive and
ducks and chickens are killed cruelly by predators like coyotes and birds
of prey. But when we have a say in the matter,
we prefer to be kind.
For cattle, this means that we speak to them gently and never use force
like cattle prods. When we want them to go from one pasture to another, we
open the gate. Often that is enough for a few to see if the grass is really
greener there (it usually is) and for the rest to follow. If not, we walk
around with our arms extended so they think we are huge beings and move
away from us toward the gate. If we want them to follow us for a distance,
we rattle an empty or full bag of their favorite treat, alfalfa pellets:
then they will usually follow us for long distances. Of course, if we have
it, we then give them the alfalfa.
There are many other aspects to raising cattle humanely, and there are
several third-party organizations that audit and certify operations like
ours. Of these, according to Consumer
Reports, the best is A Greener
World. We have been certified by them since 2018.
Is there an advantage to certified organic meat? What does that mean, anyway?
The National Organic Program is a legal standard of the government of the United States of America. It regulates
use of the term Certified Organic for all products that can carry that label.
The standards are complex in detail but basically
very simple: certified products may not come in contact in any way with
any forbidden substances, and pretty much all synthetic substances are
forbidden. For crops, this means no pesticides, no synthetic fertilizers,
no hormones, no use of genetically modified seed, and so forth. For
livestock, this means no antibiotics, no hormones, no growth stimulants,
and no food that is not itself certified organic. It also means that animal
byproducts are never used.
How important are these standards? Opinions of course vary, but we suggest consideration of residues of antibiotics and of pesticides.
Pesticide residues are monitored by the United States Centers for Disease Control has a web page discussing the pesticides in our environment, their health effects, and some ways to avoid them.
A recent report by the Environmental Working Group reviewed the data from the USDA Pesticide Data Program and listed a number of vegetables and fruits that were found to have higher and lower levels of pesticides. The reference list of that report includes a number of interesting papers published in peer-reviewed journals, including:
If I eat certified organic, certified grass-fed beef, will I lose weight? Become healthy, wealthy, and wise?
Weight. Only if you consume fewer calories than your body is using. Interesting note: much of the energy we eat goes into black body radiation as a price we pay for being warm-blooded. Be sure to eat enough protein so your body doesn't eat up your muscles (but check with your doctor if you have medical conditions like impaired kidney function).
Healthy. We hope so but clinical studies so far do not show an advantage to eating organic and/or grassfed meat.
Wealthy. This is hard to say: healthier foods tend to be more expensive, but may help people function more effectively and thus perhaps become wealthier.