Meat is a highly controversial food.

On one hand, it's a staple in many diets and is a great source of protein and important nutrients.

On the other hand, some people believe eating it is unhealthy, unethical and unnecessary.

This article takes a detailed look at the health benefits and potential risks of eating meat.

Meat is the flesh of animals that humans prepare and consume as food.

In the US and many other countries, the term mainly refers to muscle tissue of mammals and birds. It is typically consumed as steak, chops, ribs, roast or in ground form, like hamburger.

In the past, offal such as liver, kidneys, brains and intestines were commonly enjoyed in most cultures. However, most Western diets now exclude them.

Nevertheless, offal remains popular in some parts of the world, particularly among traditional societies. Many delicacies are also based on organs.

Foie gras is made from duck or goose liver. Sweetbreads are thymus glands and pancreas. And menudo is a soup made from intestines.

Today, most meat worldwide comes from domesticated animals raised on farms, mainly large industrial complexes that often house thousands of animals at a time.

However, in some traditional cultures, hunting animals remains the sole means for obtaining it.

Bottom Line: Meat refers to the muscle or organs of an animal consumed as food. In most parts of the world, it comes from animals raised on large industrial farms.

Types of meat are categorized by their animal source and how they are prepared.

Red Meat

This comes from mammals and contains more of the iron-rich protein myoglobin in its tissue than white meat. Examples include:

  • Beef (cattle).
  • Pork (pigs and hogs).
  • Lamb.
  • Veal (calves).
  • Goat.
  • Game, such as bison, elk and venison (deer).

White Meat

This is generally lighter in color than red meat and comes from birds and small game. Examples include:

  • Chicken.
  • Turkey.
  • Duck.
  • Goose.
  • Wild birds, such as quail and pheasant.

Processed Meat

Processed meat has been modified through salting, curing, smoking, drying or other processes to preserve it or enhance flavor. Examples include:

  • Hot dogs.
  • Sausage.
  • Bacon.
  • Luncheon meats, such as bologna, salami and pastrami.
  • Jerky.
Bottom Line: Meat comes from a variety of different animals and is classified as either red or white, depending on the source. Processed products have been modified with additives to enhance flavor.

Lean meat is considered an excellent protein source. It contains about 25-30% protein by weight after cooking.

3.5 oz (100 grams) of cooked chicken breast contains about 31 grams of protein. The same serving of lean beef contains about 27 grams (1, 2).

Animal protein is a complete protein, meaning it provides all 9 essential amino acids.

A 3.5-oz (100-gram) portion of lean beef provides (2):

  • Calories: 205.
  • Protein: About 27 grams.
  • Riboflavin: 11% of the RDI.
  • Niacin: 19% of the RDI.
  • Vitamin B6: 16% of the RDI.
  • Vitamin B12: 19% of the RDI.
  • Niacin: 63% of the RDI.
  • Phosphorus: 24% of the RDI.
  • Zinc: 50% of the RDI.
  • Selenium: 28% of the RDI.

The nutrient profiles of other muscle meats are similar, although they contain less zinc. Interestingly, pork is especially high in the vitamin thiamine, providing 63% of the RDI per 3.5 oz (100 grams) (3).

Liver and other organs are also high in vitamin A, vitamin B12, iron and selenium. They're also an excellent source of choline, an important nutrient for brain, muscle and liver health (4).

Bottom Line: Meat is an excellent source of protein and several vitamins and minerals, including vitamin B12, niacin and selenium.

Cooking and preparing meats in certain ways may negatively affect your health.

When they're grilled, barbecued or smoked at high temperatures, fat is released and drips onto hot cooking surfaces.

This produces toxic compounds called polycyclic aromatic hydrocarbons (PAHs) that can rise up and seep into the meat.

PAHs are carcinogenic, meaning they can cause cancer. However, minimizing smoke and quickly wiping away drippings can reduce PAH formation by up to 89% (5, 6, 7).

Heterocyclic amines (HAs) are formed when meat is heated to high temperatures and forms a dark crust. HA levels have been shown to rise during extended cooking times and with lengthy cooling down after cooking (8, 9).

Nitrates are additives in processed meats that were formerly considered carcinogenic, but are now considered harmless or even beneficial.

However, researchers disagree about whether similar additives known as nitrites (with an "i") increase cancer risk (10, 11).

Bottom Line: Cooking food at high temperatures or for long periods of time can increase the production of toxic byproducts capable of causing cancer.

Many people claim that eating meat raises cancer risk. However, this largely depends on the type you eat and how it's cooked.

Is Red Meat Bad?

Some observational studies link a high red meat intake to several types of cancer, including digestive tract, prostate, kidney and breast cancers (12, 13, 14, 15, 16, 17, 18, 19).

However, in nearly every study, the association was between cancer and well-done meat, PAHs or HAs, rather than red meat itself. These studies indicate that high-heat cooking had a very strong effect.

Of all cancers, colon cancer has the strongest association with red meat intake, with dozens of studies reporting a connection.

Aside from a few studies that didn't distinguish between processed and fresh meat or cooking method, increased risk seems to occur mostly with higher intake of processed and well-done meat (20, 21, 22, 23, 24, 25).

In a 2011 analysis of 25 studies, researchers concluded that there was insufficient evidence to support a clear-cut link between red meat and colon cancer (22).

Other Factors That May Affect Cancer Risk

While red meat cooked at high temperatures may increase cancer risk, white meat doesn't seem to. In fact, one study found that poultry consumption was linked to a reduced risk of colon cancer, even when cooked to the point of charring (20, 22, 24).

Animal and observational studies suggest that, in addition to toxic compounds created during high-heat cooking, heme iron found in red meat may play a role in colon cancer development (26, 27).

In addition, some researchers believe processed meat may potentially lead to inflammation in the colon that increases cancer risk (28).

In one study, adding calcium or vitamin E to cured meat reduced levels of toxic end-products in the feces of humans and rats. What's more, these nutrients were found to improve pre-cancerous colon lesions in the rats (29).

It's important to realize that because these studies are observational, they only show a relationship and cannot prove that red or processed meat causes cancer.

However, it definitely seems wise to limit your consumption of processed meat. If you choose to eat red meat, then use gentler cooking methods and avoid burning it.

Bottom Line: Observational studies have shown a link between well-done or processed meat and increased risk of cancer, especially colon cancer.

Several large observational studies exploring meat intake and heart disease have found an increased risk with processed products. Only one study found a weak association for red meat alone (30, 31, 32, 33).

In 2010, researchers performed a massive review of 20 studies with over 1.2 million people. They found that consuming processed — but not red — meat appeared to increase heart disease risk by 42% (30).

However, these studies don't prove that a high intake of processed meat causes heart disease. They only suggest that there may be a relationship.

Some controlled studies have found that frequent meat consumption, including high-fat varieties, has a neutral or positive effect on heart disease risk factors (34, 35).

Bottom Line: Processed meat has been linked to heart disease in some studies, while controlled studies have shown that meat may have a neutral or beneficial effect.

Several large studies have also shown an association between processed or red meat and type 2 diabetes (30, 36, 37, 38, 39, 40, 41).

One review of three studies found that consuming more than half a serving of red meat daily increased the risk of developing diabetes within four years by 30%, in part related to weight gain (37).

However, it's possible that the people who ended up with diabetes had engaged in unhealthy behaviors, such as consuming too many refined carbs, eating too few vegetables or simply overeating in general.

In studies on low-carb diets, which tend to be high in meat, blood sugar levels and other diabetes markers tend to go down (42).

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

A high intake of red and processed meat has been linked to obesity in several observational studies.

This includes a review of 39 studies with data from over 1.1 million people (43).

However, the results from individual studies varied greatly (43).

In one study, researchers found that although there was a relationship between frequent red meat consumption and obesity, people who ate the most also took in about 700 more calories daily than those who ate less (44).

Again, these studies are observational and don't account for other types and amounts of food consumed on a regular basis.

And although red meat is frequently linked to obesity and weight gain while white meat isn't, one controlled study found no difference in weight changes among overweight people assigned to eat beef, pork or chicken for three months (45).

Another study in people with prediabetes found that weight loss and body composition improvements were similar whether subjects consumed diets based on animal or plant protein (46).

Consuming fresh, whole foods appears to benefit weight loss, regardless of whether meat is consumed or not.

In one study, 10 obese postmenopausal women followed an unrestricted paleo diet with 30% of calories as mainly animal protein, including meat. After five weeks, weight decreased by 10 lbs (4.5 kg) and belly fat decreased by 8%, on average (47).

Bottom Line: While some observational studies have linked red and processed meat intake to obesity, overall calorie intake is key. Controlled studies have shown that weight loss can occur despite high meat intake.

Eating meat has several health benefits:

  • Reduced appetite and increased metabolism: Many studies have shown that high-protein diets that include meat increase metabolic rate, reduce hunger and promote fullness (48, 49, 50, 51).
  • Retention of muscle mass: Animal protein intake is consistently linked to increased muscle mass. In one study in older women, eating beef increased muscle mass and also reduced markers of inflammation (52, 53, 54, 55, 56).
  • Stronger bones: Animal protein may improve bone density and strength. In one study, older women with the highest intake of animal protein had a 69% decreased risk of hip fractures (57, 58).
  • Better iron absorption: Meat contains heme iron, which your body absorbs better than non-heme iron from plants (59, 60, 61).
Bottom Line: Meat has benefits for appetite, metabolism, iron absorption and the health of your muscles and bones.

Some people choose not to eat meat because they don't believe in killing animals for food when there are other ways to meet nutrition needs.

This is a valid point of view that should be respected.

Others object to animals being raised in large, industrial complexes that are sometimes referred to as "factory farms," which is also very understandable.

These farms are overcrowded and often don't allow animals to get sufficient exercise, sunlight or room to move. To prevent infection, livestock are often given antibiotics, which can lead to antibiotic resistance (62, 63).

Many animals are given steroid hormones like estrogen, progesterone and testosterone to speed growth. This raises additional health and ethical concerns (64).

The environmental effects of factory farming have also been criticized, particularly the waste produced during raising and slaughtering, as well as the high cost of grain-based meat production (63, 65, 66, 67).

Fortunately, there are alternatives. You can support small farms that raise animals humanely, don't use antibiotics or hormones and provide their animals with natural diets.

Bottom Line: Some object to killing animals for food, inhumane conditions on industrial farms or the environmental effects of raising livestock.

Here's how to ensure you're consuming meat in a way that's healthiest for you and the planet:

  • Choose fresh products: Fresh meat will always be healthier for you than processed varieties.
  • Give organ meats a try: Add these 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: These are high in fiber, contain valuable antioxidants and help make your diet well balanced.
  • Choose organic meat from small farms: This is more environmentally friendly and better from an ethical perspective.
  • 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 and antioxidants (68, 69, 70).
Bottom Line: To maximize benefits and and minimize risk, choose fresh meat, avoid high-heat cooking, include plant foods in your diet and choose organic or grass-fed whenever possible.

Unprocessed and properly cooked meat has many nutrients and may have some health benefits. If you enjoy eating meat, then there is no compelling health or nutritional reason to stop.

However, if you don't feel right about eating animals, you can also stay healthy by following a well-balanced vegetarian diet.

Ultimately, whether you consume meat is a personal choice and one that others should respect.

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