The meat debate is both complicated and divisive. Nutrition experts have sent mixed messages for years. The conversations are not only about meat’s direct health effects but also its environmental effects.

There are reasons to eat meat and to avoid it, but few people can agree on just what meat does for our bodies or how it affects the planet. Some people consider meat to be a fantastic source of nutrients, while others argue that it’s harmful to human health.

For every claim that meat might cure a chronic illness, there seems to be another claim implying that meat causes heart disease and cancer.

Some sources say meat is environmentally-friendly, and others say meat production contributes to deforestation.

This article attempts to untangle the meat debate from a health-based perspective and uncover the pros and cons of eating meat.

The prepared ingredients for steak fajitas — including meat, veggies, and cheese — on a table.Share on Pinterest
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Meat is the flesh and other edible parts of animals, such as mammals and birds, that humans prepare and consume.

In the United States and many other countries, the term “meat” mainly refers to the muscle tissue and fat of mammals and birds. But meat may also include other edible tissues, such as organs.

Offal — particularly liver, kidneys, brains, and intestines — has historically been eaten in most civilizations. However, it’s fallen out of favor in some parts of the West. Offal remains popular in various cultures throughout the world, particularly among traditional societies.

Many delicacies are also organ-based.

Foie gras is a traditional French specialty made from duck or goose liver. Sweetbreads comprise meat from the thymus gland and have been eaten in Europe since Roman times, and Menudo is a traditional meat dish in Mexico including beef stomach (tripe) and meat in broth.

Nowadays, meat is produced on farms. Most commercial meat products come from domesticated animals kept in huge industrial facilities that may house hundreds or even thousands of animals at once.

In some traditional societies, though, hunting animals is the only way to obtain meat.

Meat is generally eaten after it has been cooked, sometimes after being cured or smoked. It’s often eaten as steak, chops, ribs, or roast and can also be found in powdered or ground forms.

Meat can be cooked in or served with a sauce, condiment, or side dish, which may be dipped into the meat juices.

Summary

Meat is the flesh or organs of an animal consumed as food. In most parts of the world, it comes from animals raised on large industrial farms.

Meat is classified according to the animal from which it comes, as well as how it’s prepared.

Red meat

Red meat is higher than white meat in myoglobin, a protein that’s high in iron and found only in mammals. The following are some examples:

  • beef (cattle)
  • pork (pigs and hogs)
  • lamb
  • veal (calves)
  • goat
  • game, such as bison, elk, and venison (deer)

White meat

White meat refers to flesh that is light in color before and after cooking, as opposed to red meat. The phrase often includes all birds, even if their flesh appears red in reality, as in the case of duck meat. Other examples include:

  • chicken
  • turkey
  • goose
  • wild birds, such as quail and pheasant

Processed meat

The term “processed meat” refers to red or white meats that have been “treated” in some way. It might be preserved or enhanced in various forms, such as by salting, curing, smoking, drying, or other processes. Examples include:

  • hot dogs
  • sausage
  • bacon
  • luncheon (deli) meats, such as bologna, salami, and pastrami
  • jerky
Summary

Meat comes from animals and is classified as either red or white, depending on the source. Processed meats have been modified with additives to enhance flavor.

Fresh meat is regarded as a valuable source of high quality protein.

When a protein contains all 9 amino acids (the building blocks of protein) that your body needs in adequate amounts, it’s thought to have high biological value and can be considered a complete protein (1).

After cooking, meat contains approximately 25–30% protein by weight.

A 3.5-ounce (100-gram) serving of cooked chicken breast contains about 31 grams of protein, while the same serving size from beef provides 27 grams.

Here’s a look at the nutritional content of a 3.5-ounce (100-gram) serving of lean beef (2):

  • Calories: 205
  • Protein: about 27 grams
  • Riboflavin: 15% of the Daily Value (DV)
  • Niacin: 24% of the DV
  • Vitamin B6: 19% of the DV
  • Vitamin B12: 158% of the DV
  • Iron: 16% of the DV
  • Phosphorus: 19% of the DV
  • Zinc: 68% of the DV
  • Selenium: 36% of the DV

Other muscle meats have similar nutrient profiles, although they contain less zinc.

Pork is particularly rich in thiamine. For example, pork chops provide 78% of the DV per 5.5-ounce (157-gram) serving (3).

Vitamin A, B12, iron, and selenium are present in significant amounts in liver and other organ meats. These meats are also excellent sources of choline, an important nutrient for brain, muscle, and liver health (4, 5).

Summary

Meat is a rich source of protein and several vitamins and minerals, including vitamin B12, niacin, and selenium.

How cooking methods may affect meat’s carcinogenic effects

Meat may be detrimental to your health if you cook and prepare it in certain ways.

High temperatures used to cook meat, especially red meat, have been linked to the formation of cancer-causing compounds.

As meats cook at scorching temperatures, their fats seep out and accumulate on the hot cooking surface. In the process, toxic compounds called polycyclic aromatic hydrocarbons (PAHs) are formed. PAHs may collect in the meat and build up over time (6, 7).

PAHs could be harmful to human health since they are carcinogenic (cancer-causing). However, reducing smoke and quickly removing drippings may reduce PAH formation by up to 89% (6, 7, 8).

Grilling, frying, and roasting meat at high temperatures can create heterocyclic aromatic amines (HAAs), which have been linked to cancer in long-term animal studies (9).

HAA levels appear to increase when food is cooked for a long period of time. Storing or ripening meat in the fridge for many days may raise HAA levels, as reported in an older study (9, 10).

But according to the International Agency for Research on Cancer (IARC) — an authority of the World Health Organization — there isn’t enough evidence to determine whether a meat’s cooking method affects your cancer risk (11).

While red meat cooked at high temperatures may increase cancer risk, white meat may not have the same effect, although data is still unclear.

An earlier study found that poultry consumption was linked to a reduced risk of colon cancer — even when cooked to the point of charring (12, 13).

Reviewing the links between nitrates and cancer

Nitrates and nitrites can be found naturally in food, but they’re also artificial ingredients that may be added for various reasons, including preserving meats during processing.

While nitrate is generally harmless, your gut transforms some of the nitrate you eat into nitrite.

The conversion to nitrite — and its digestion — is linked to harmful side effects. It’s associated with a higher risk of cancer (14).

On the other hand, some studies suggest that the nitrate conversion process also produces nitric oxide. This compound may help regulate blood pressure and promote heart health (14).

More research is needed to determine how the nitrates or nitrates in meat products affect human health.

Summary

Meat cooked at high temperatures has been linked to cancer-causing compounds. Yet, cooking methods’ effects on cancer risk are unclear. When nitrates are ingested, they’re converted into nitrites, which may be associated with increased cancer risk.

Meat consumption and cancer risk

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Some people insist that eating meat raises cancer risk. However, that probably depends on the type of meat you eat.

There is convincing evidence that eating processed meat leads to cancer, especially colorectal cancer. The IARC reviewed epidemiological research linking cancer in humans with eating processed meats (11).

Furthermore, there is strong — but limited — evidence linking red meat consumption to colorectal cancer. Pancreatic and prostate cancers have likewise been connected. As a result, the IARC classifies red meat as “probably carcinogenic to humans” (11).

Other research links a high intake of red meat to cancers of the digestive tract, kidney, and bladder (15, 16, 17).

Although no definite link between eating meat and breast cancer has been established, diet may significantly influence breast cancer prognosis.

Eating a healthy diet high in fruits, vegetables, and whole grains and low in meat may improve outcomes of early-stage breast cancer (18).

A recent review of observational and experimental studies suggests that eating meat may induce direct DNA damage, which is known as genotoxicity. However, the researchers acknowledged that some of the studies in the review were flawed (19).

Of all cancers, colon cancer has the strongest association with processed and red meat intake, with dozens of studies documenting a link.

Overall, more high quality research is needed to further explore the relationships between meat and cancer.

Other factors that may affect cancer risk

In addition to potentially harmful compounds generated during high heat cooking, the heme iron present in red meat has been linked to colon cancer development (20, 21).

Furthermore, some scientists believe that processed meat may provoke inflammation in the colon, which raises cancer risk (22).

However, there may be ways to reduce the risk.

Adding dried red wine, pomegranate extract, and vitamin E to cured meat reduced levels of toxic end products in the urine and feces of rats. What’s more, these nutrients were found to improve precancerous colon lesions in the rodents (23).

And because these findings are observational and some are based on animal research, it’s important to keep in mind that they don’t necessarily prove that red meat causes cancer.

Observational studies are used to develop theories, and intervention trials are utilized to evaluate them. Observational research only suggests connections; after that comes the phase of an intervention study to confirm or reject those observations.

It is, however, a good idea to limit how much processed meat you eat. If you consume red meat, cook it more gently and avoid burning it.

Summary

Processed meats are linked to cancer, with the strongest evidence linking it to colorectal cancer. Red meat is probably carcinogenic.

A significant number of large observational studies have linked meat consumption to a higher chance of developing heart disease (24, 25, 26, 27, 28).

Recent research including 43,272 men found that eating unprocessed or processed red meat was linked to a slightly increased risk of heart disease (24).

In an older review of 20 studies among more than 1.2 million people, researchers found that consuming processed meat appeared to increase heart disease risk by 42%. Although, they didn’t uncover a link between red meat and heart disease (29).

One study found that people who ate a diet high in red meat had three times the amount of trimethylamine N-oxide (TMAO) — a compound linked to heart disease — compared with those who ate a diet heavy in white meat or plant-based protein (30).

However, these studies don’t prove that a high intake of meat causes heart disease. They only show an association.

Additionally, some controlled studies and older research have found that frequent meat consumption, including high fat varieties, has a neutral or beneficial effect on heart disease risk factors (31, 32).

Summary

Large studies have linked the consumption of processed or unprocessed meat to heart disease. Some controlled studies have shown that meat may have a neutral or beneficial effect.

Several large studies have shown an association between processed or red meat and type 2 diabetes (33, 34, 35, 36, 37, 38, 39).

Eating meat raises the risk of type 2 diabetes by 22%, according to a recent meta-analysis of epidemiological research (34).

An older review of 3 studies found that consuming more than half a serving of red meat daily increased the risk of developing diabetes within 4 years by 30%, in part related to weight gain (40).

However, the science of nutrition is anything but straightforward.

It’s likely that those who developed diabetes had other contributing risk factors, such as genetic or environmental factors. Dietary behaviors may have also played a role, including eating too many refined carbs, consuming insufficient vegetables, or consistently overeating.

Any of the above could have contributed to these participants’ risk status.

Summary

Some observational studies show a relationship between red and processed meats and increased diabetes risk. However, this may also depend on other dietary factors.

Several observational studies, including a review of 39 studies including over 1.1 million people, have linked high intakes of red and processed meat to increased body weight (41).

However, more research is needed, as the relationship between meat consumption and weight gain isn’t totally clear.

For example, the results from individual studies vary greatly (42).

Plus, these studies are observational, and they don’t account for other types and amounts of food consumed regularly. It’s also important to remember that many factors aside from diet can influence a person’s weight, such as genetics, sleep quality, and activity level.

A study of 170 countries’ obesity rates found that the availability of meat explained 50% of the variation in rates after adjusting for wealth, calorie consumption, urbanization levels, and physical inactivity, all of which significantly contribute to increased body weight (43).

In other words, high meat availability may be associated with an increased prevalence of obesity.

Although red meat is frequently linked to weight gain and white meat isn’t, one controlled study found no difference in weight changes among people with excess weight who were assigned to eat beef, pork, or chicken for 3 months (44).

Another study in people with prediabetes found that weight loss and body composition improvements were similar among those who consumed diets based on animal or plant protein (45).

Either way, it appears that consuming a plant-heavy or plant-based diet supports healthy weights, regardless of whether meat is consumed.

A plant-heavy diet should be rich in whole foods, which are minimally or not at all processed, especially fresh fruits and vegetables.

But that doesn’t mean meat can’t fit into a well-rounded diet.

For example, a recent meta-analysis revealed that the Paleolithic (paleo) diet — which centers whole foods, includes meat, and excludes grains and processed foods — might help people lose weight, reduce their waist circumference, and help manage chronic disease (46).

The paleo diet is a subset of diets that follow what many proponents believe to be the eating patterns of people during the Paleolithic era. It comprises lean meats, fish, fruits, vegetables, nuts, and seeds — foods that may have been hunted or foraged in the past.

To verify its health advantages, however, more randomized clinical trials with a larger number of participants and longer duration are required.

If you’re considering changing to a plant-based, paleo, or other diet plan, be sure to talk with a healthcare professional first. They can help you explore new eating habits while ensuring you get the nutrients you need and maintain a healthy relationship with food.

And remember, no one dietary pattern or preference is necessarily the “healthiest” or best to follow for everyone.

Summary

While some observational studies have linked red and processed meat intake to higher weights, more robust research is needed.

Meat, along with fish, eggs, soy, and legumes, is a high protein food that may provide certain health benefits:

  • Reduced appetite and increased metabolism. Numerous studies have shown that high protein diets increase metabolic rate, reduce hunger, and promote fullness (47, 48, 49).
  • Retention of muscle mass. Higher protein intakes are linked to increased muscle mass (50, 51, 52, 53).
  • Stronger bones. Protein is an essential nutrient for bone health. Food sources appear to have a protective influence and ultimately reduce fracture risk (54).
  • Better iron absorption. Meat contains heme iron, which your body absorbs better than non-heme iron from plants. However, certain foods can support the absorption of non-heme iron from plant sources (55).
Summary

Protein-rich foods have benefits for muscle and bone health, appetite, metabolism, and iron absorption.

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Meat is a significant source of nutrients. Still, it’s clear that excessive consumption of this protein source can have unfavorable effects on the environment.

Livestock farming has a detrimental influence on several environmental factors, including greenhouse gas emissions, deforestation, water pollution, and water shortages (56, 57).

In any case, the effect of grassland management for cattle on carbon storage is uncertain. Some experts claim that it might help increase carbon storage in pasturelands. Still, the overall effect is expected to be minor (58).

Additionally, meat consumption — particularly wild meat — is linked to viral infections, as numerous viruses have been discovered in meat marketplaces (59).

Some people choose not to eat meat because they do not believe that animals should be killed for food when other options exist to meet their nutritional needs.

Others object to animals being raised in large industrial complexes that are sometimes referred to as factory farms.

Many of these farms are overcrowded and don’t allow adequate exercise, sunshine, or space for the animals to move. Antibiotics are frequently given to livestock to prevent infection, which can result in antibiotic resistance (60).

Many animals are administered steroid hormones, such as estrogen, progesterone, and testosterone, to speed their growth. That raises additional health and ethical concerns (61, 62).

The environmental effects of factory farming have also been criticized, particularly the waste produced during raising and slaughtering and the high cost of grain-based meat production (63, 64, 65).

Fortunately, there are alternatives. You can support small farms that raise animals compassionately, follow better farming practices, avoid antibiotics or hormones, and feed animals natural diets.

Summary

The overconsumption of meat has a high environmental, and meat has been linked to viral infections. Some people object to killing animals for food and the inhumane conditions on industrial farms.

If you eat meat, keep the following things in mind:

  • Choose unprocessed products. Unprocessed meats have been associated with cancer to a lesser extent than commercially processed ones.
  • Give organ meats a try. Explore organ meats as a complement to your diet to take advantage of their high nutrient content.
  • Minimize high heat cooking. If you grill, barbecue, or use another high heat method, wipe away drippings right away and avoid overcooking or charring.
  • Consume unprocessed, plant-based foods. Plant-based diets are associated with a reduced risk of chronic diseases. They are also more environmentally sustainable and less expensive.
  • Choose organic meat from small, local farms. This is a more environmentally-friendly option and better aligned with many people’s ethical perspectives.
  • Select grass-fed beef. Cattle that consume a natural diet of grass — rather than grain — produce meat that is higher in healthy omega-3 fatty acids. Also, older evidence indicates higher levels of antioxidants in pasture-fed cattle (66, 67).
Summary

To maximize benefits and minimize risk, consider unprocessed meat, avoid high heat cooking, include plant foods in your diet, and choose organic or grass-fed whenever possible.

Meat has been a staple of the human diet for thousands of years. It’s a rich source of protein, which provides health benefits for the body.

Yet, processed meats are linked to cancer, with colorectal cancer research revealing the most compelling evidence.

And processing and cooking meat at high temperatures has been associated with the production of cancer-causing chemicals. What effects different cooking methods have on cancer risk is not yet clear.

What’s more, eating meat may be linked to heart disease, diabetes, and weight gain. However, this is primarily based on observational studies.

Finally, the overconsumption of meat has a high environmental impact, along with a connection to viral infections.