Many people are concerned about whether they should eat or not eat any meat. Documentaries such as The Game Changers or Forks Over Knives helped popularize vegan and vegetarian lifestyles, and cast doubt on those choosing the omnivore way of life. Is the demonization of meat justified, though? Let’s examine the science. You probably already have an idea.
Correlation vs. causation
It is important to distinguish between observational and randomized controlled studies in order to understand scientific research. This is especially true for nutrition. Nutrition science, which is largely observational in nature, relies heavily on nutritional epidemiology. This means that researchers will look at large groups of people, and track their habits, choices in diet, etc. In order to determine the cause, researchers will try to observe (aka find) an association between certain factors and specific diseases/conditions. Unfortunately, nutritional epidemiology is unable to determine cause and can only provide weak data to make recommendations.
Meat cons
Carcinogens
It has been proven that certain substances increase the risk of cancer. Heterocyclic amines and polycyclic aromatic hydrocarbons are produced when meat is heated to high temperatures. Animal studies also show that heme-iron-rich red meat can be toxic to cells. However, the components of a meal and nutrients can alter how these chemicals impact health. One 2021 controlled, randomized trial showed that 1 cup of cooked greens per day could help offset the inflammation and colon cell damage caused by red meat consumption. For example, the International Agency for Research on Cancer’s (IARC) recommendations are based on a large number of observational studies (more than 800 epidemiological ones). IARC, the World Health Organization ‘s IARC, reports that there are limitedevidences that red meat is carcinogenic. The consumption of beef, pork and lamb is linked to colorectal carcinoma, while processed meat can cause colon cancer. The World Cancer Research Fund (WCRF), Harvard School of Public Health and the 2015-2020 American Guidelines recommend limiting red, processed, or unprocessed meat.
Low in nutrient density
Although meat is rich in certain nutrients, such as B12, it does not contain other nutrients that are beneficial to health, such as phytochemicals that prevent cancer and fibers which support the gut. These nutrients can be found in plants. In a 2021 controlled randomized feeding-trial, participants who consumed fried meat for four weeks had a negatively affected microbiome. They also experienced worsened glucose control and inflammation.
High in saturated fat
Some populations at risk may have to reduce their intake of saturated fat. Red meat contains more saturated fats than poultry and seafood, which can be harmful for people with diabetes, Alzheimer’s, or cardiovascular disease. A randomized controlled trial concluded that poultry and white meat were not superior to red in terms of cardiovascular disease risk when saturated fat levels were kept low.
Potential meat pros
Protein needs
The International Protein Board suggests that protein intake be above the Recommended Daily Allowance (RDA), which is 0.8g/kg. This will prevent any protein deficiencies. For most adults, the recommended range is 1.1-1.8g/kg (0.5-0.8 g/lb), excluding athletes who may require more. This includes those who want to maintain or build muscle mass, while aging and losing weight.
Weight & Satiety
In order to manage weight, it is important to control calorie intake. The macronutrient protein is responsible for the satiety, delayed onset hunger and preservation of muscle mass when weight loss or aging occurs. In light of the obesity epidemic that is spreading around the world, increasing protein intake by eating meat can help to reduce weight, outweigh any potential risks and provide greater meal and diet satisfaction despite fewer calories.
B12
Vitamin B12, also known as water-soluble Vitamin B12, is a vitamin that you cannot produce in your body. Adequate B12 consumption has many benefits, including helping to form blood cells, reducing inflammation, reducing risk of depression, protecting brain cells, improving energy production, and ensuring healthy nerve function. Most meats, eggs, dairy products, and seafood are rich in B12 as well as vegetarian sources like fortified nutritional yeast and non-dairy milk.
Leucine
muscle synthesis is essential for after exercise . Leucine deficiency can affect muscle growth and maintenance. Below are whole food sources that contain more than 1,000mg of leucine per serving, as reported by the USDA FoodData Central Database.
- Chicken cooked, diced/chopped – 2000mg for 3 ounces.
- Beef, cooked – 1820mg per 3 ounces.
- Turkey, cooked – 1710mg per 3 ounces.
- Navy beans in cans – 1670mg/cup
- Wild Atlantic salmon, cooked – 1370mg/ 3 ounces.
- Lentils, cooked – 1300mg per cup.
- Yogurt, Greek – 1211mg per cup.
- Cottage cheese, 2% low fat – 1185mg per 1/2 cup.
- Almonds whole – 1050mg in 1/2 cup.
Consensus?
The Annals of Internal Medicine has published six papers written by researchers within the Nutritional Recommendations & accessible Evidence summaries Composed of Systemsatic Reviews (NutriRECS). This was done to clarify the epidemiology based red meat concerns using a more robust science approach. These papers were designed to evaluate the impact of unprocessed red meat and processed red beef on cardiovascular disease, cancer, and mortality. The first report summarized the group recommendations. Adults can continue eating meat at current levels, as current evidence is too weak to recommend restricting intake.
To make accurate and reliable recommendations for the entire population, randomized controlled studies and mechanistic research are more important than observational data and personal experience. Future research could reveal different conclusions, but it seems that red meat consumption as is part of a healthy, omnivore-based diet (not the dangerous Standard American Diet, which emphasizes meat, sugar and low vegetables) does not negatively impact health. It may even help to increase nutrient intake and improve weight loss, muscle mass and body composition. If you are at high risk for colorectal carcinoma or want to be extra careful, it is prudent to limit the consumption of processed meats and saturated fats, to reduce your intake of grilled and barbecued meats, and to serve meat with vegetables rich in antioxidants and fiber.
All of us tend to have our own nutrition preferences because we eat several times per day. What works for one person may not be the best for another. You can work with a dietitian who will help you customize your diet and lifestyle in order to achieve your health goals. This includes your meat consumption.
