Is red meat healthy or harmful? Should you enjoy it freely on your low-carb, keto diet, or limit your consumption?
Depending on which expert you ask, those questions may receive a very different answer.
However, has a truly strong link between red meat and heart disease, cancer, or other diseases been established? Will consuming it on a regular basis shorten your life or put you at risk of health problems?
Here is our guide to what we currently know about red meat, so you can make an informed decision about whether to include it in your own diet and, if you do, how much of it you may decide to eat each week.
What is "red meat"?
Red meat comes from mammals. When raw, it usually appears dark red because it contains a lot of myoglobin, the iron-rich protein that stores oxygen in animal muscle. The red meat category includes beef, pork, lamb, veal, goat, bison, venison and other game. The term "red meat" can be a bit confusing, though, since veal and pork flesh are often light in color while duck, as well as salmon and some other fish are reddish. However, when discussing meat from a nutritional standpoint, "white meat" refers to poultry and fish, which contain less myoglobin and iron than red meat.
Red meat can be fresh or processed. Fresh red meat is exactly what it sounds like: meat that contains no additives, requires refrigeration, and needs to be consumed within a few days, after roasting, grilling, or stewing etc.
Processed red meat is a broader term referring to meat that's been modified by salting, curing, smoking, canning, or treating with preservatives. Popular types include bacon, salami, sausage, hot dogs, and jerky. The shelf life of various processed meats span a very wide range; certain types last for only a few days in the refrigerator, while dried or canned types can remain edible for several months or even years when stored at room temperature. Additionally, some processed meats contain salt as their sole additive, whereas others may include sugar, starch, other fillers, and chemicals such as nitrites.
Benefits of eating red meat
Animal foods are an important part of our evolutionary past, playing critical roles in our development as a species. Meat in particular has been credited with allowing us to develop the large, complex brains that are unique to humans. Indeed, we may be genetically wired to enjoy the flavor and texture of meat from a very early age.
In addition to being tasty and filling, red meat provides many nutritional benefits:
- High-quality protein: A 100-gram (3.5-ounce) serving of red meat contains about 20-25 grams of protein, depending how fatty it is (leaner cuts have more protein). Like eggs, dairy, and other animal products, red meat provides protein that is considered complete, meaning it contains all nine essential amino acids in the optimal amounts your body needs. Learn more about protein:
Protein on a low-carb or keto diet
Guide Along with fat and carbohydrates, protein is one of the three macronutrients ("macros") found in food, and it plays unique and important roles in the body. Here's a guide to everything you need to know about protein on a low-carb or keto lifestyle.
- Several vitamins and minerals: Red meat is an excellent source of many important micronutrients, including vitamin B12, niacin, selenium, and zinc. A 4-ounce (114-mg) serving of red meat also provides about 400-500 mg of potassium - the same or more than you'd get in an average-size banana (422 mg).
- May help preserve muscle: It's an unfortunate fact that we usually lose muscle as we age due to hormonal and other physiological changes. In one study, older women who consumed 160 grams (5.6 ounces) of red meat six days a week in combination with resistance training achieved greater gains in lean muscle and strength than the resistance-training-only group. Similar improvements have been shown in studies of young and middle-aged men who consumed beef and triathletes who took beef-based supplements, when compared to men of similar age who ate lacto-ovo vegetarian diets or took whey-based supplements during strength training.
What does the research show with respect to meat's potential harm?
Over the past several years, no doubt you've noticed that news media have increasingly featured studies showing an association between eating a lot of red meat and increased risks of cancer and heart disease. Some articles have even stated that meat is flat-out " killing us." But how strong are these associations? Moreover, is relying on results from a few observational studies without taking all available research into account giving us a truly accurate picture of meat's true effects on health? Let's take a look at the research on red meat and disease risk to date and assess the strength of the evidence.
Red meat and cancer
In October of 2015, the International Agency for Research on Cancer (IARC) issued a press release classifying processed meat as "carcinogenic" and red meat as "probably carcinogenic" in humans. Yet results of studies examining a link between meat and cancer have been decidedly mixed.
- Colorectal cancer: By far the most common type of cancer studied for its relationship to red meat, colorectal cancers, however, have shown very weak associations with high red meat intake in systematic reviews of observational research. In some cases, this association has been attributed to heterocyclic amines (HCAs) and other potentially harmful compounds that form when meat is cooked at high temperatures. The heme iron found in red meat has also been suggested as a possible risk factor for any increased association, based on findings in animal and observational studies. However, other studies have failed to show a connection between ingesting these substances and developing colorectal cancer.
Some researchers have pointed out that a clear relationship between red meat and colon cancer hasn't been established due to weak correlations and different findings among studies. They note that many other lifestyle factors, other than meat eating, could in fact be influencing results, such as high sugar and/or alcohol intake, smoking, and decreased physical activity - or even another dietary factor. Some of these factors may be contributing to the recent global steady rise in colorectal cancer among those under 40 years of age. In general, young people today are not heavy-meat eaters, in fact, they tend to adopt vegetarian or vegan lifestyles more often than older people do. Interestingly, a large UK study looking at relationships between nutrition and cancer found a slightly higher risk of colorectal cancer among vegetarians compared to meat eaters.
In contrast to the large amount of weak observational research available, very little experimental research on red meat consumption and colon cancer exists, at least in humans. One study in people with precancerous colon polyps found that drastically cutting back on red meat over a four-year period did NOT decrease the risk of polyp recurrence. Results from animal and cell studies on red meat and colorectal cancer have been mixed. Moreover, a 2017 systematic review of these experimental studies found that the meat amounts tested were frequently much larger than what most people eat, and that many didn't include potentially protective whole foods that are typically consumed in healthy, balanced diets.
Red meat and heart disease
Some studies have claimed to show a relationship between eating a lot of red meat and increased cardiovascular disease (CVD) risk, although here again, results have been inconclusive.
In a few comprehensive reviews and meta-analyses of observational studies, red meat has been weakly associated with heart disease and CVD-related death. A 2010 review found that consuming processed meat was weakly associated with an increased risk of heart disease whereas consuming red meat was not. Another showed that eating a lot of red meat was associated with a slightly increased the risk of having a stroke but it was not associated with an increased the risk of stroke-related death.
Other large reviews have failed to find any relationship between red meat and increased risk of ischemic heart disease (also known as coronary artery disease), the most common form of CVD. And recently, a meta-analysis of randomized controlled trials (considered the strongest, highest-quality evidence) showed that eating three or more servings of red meat per week had no adverse effects on CVD risk factors like cholesterol, triglyceride or blood pressure values.
For many years, health authorities have been recommending that in order to protect the health of our hearts, we should choose lean cuts of meat rather than marbled steak and other meats high in saturated fat. However, this advice may be misguided, as there really isn't any strong, convincing evidence that consuming saturated fat contributes to heart disease.
Another concern that's been raised about red meat is that it may raise levels of TMAO (trimethylamine-N-oxide) in the body, which some researchers believe may increase heart disease risk. Yet what's often not mentioned is that eating many other foods - including plants - results in the same effect. Cardiologist Dr. Bret Scher, a contributor to Diet Doctor, wrote about the inconclusive evidence for a relationship between TMAO and CVD, citing a recent study and saying: "Based on these mixed findings, the jury is still out, and we have plenty of reason to question the importance of elevated TMAO as an independent risk marker or causative factor of coronary disease."
Red meat and insulin-resistant conditions
Some studies suggest that eating red meat on a regular basis may increase the risk of diabetes and other conditions characterized by insulin resistance.
- Obesity and metabolic syndrome: A 2014 systematic review showed a weak relationship between red meat and obesity but a much stronger one between red meat and large waist size. Analysis of data from the PREDIMED trial - a large study exploring health-related effects of the Mediterranean diet - found that people who reported the highest red meat intake were more than twice as likely to develop metabolic syndrome and eight times as likely to be centrally obese (defined as having a very large waist size) as those who reported the lowest meat consumption.This association remained even after researchers made adjustments for the participants' self-reported smoking, alcohol consumption, calorie intake and physical activity.On the other hand, a well-controlled trial in overweight and obese people found that including 500 grams (about 5 servings) of lean red meat per week as part of a Mediterranean diet resulted in equal or better weight loss and reduction in metabolic risk factors compared to following the same basic diet but eating much less red meat.
Red meat and all-cause mortality
It may be difficult to count all the times you've heard that eating red meat on a regular basis could shorten your life. Although researchers may conclude that high intake of red meat has been linked to increased risk of death from any cause in several studies, the associations have always been very weak, with hazard ratios consistently under 1.4. What's more, a 2013 review of dietary habits among Asians not only found no association with increased risk of death among red meat eaters but also a slightly decreased risk of CVD mortality in men and cancer mortality in women who reported the highest intake of meat.
