Pros and Cons of vegetarian and meat diets

Recently, I was having a conversation with a friend and she expressed her confusion on which dietary pattern was the best for health - is it a vegetarian, vegan, or omnivorous diet? I think this is an excellent question because there is evidence to support all fronts, which complicates the answer. Depending on who you speak to or read from, you may get conflicting answers. I’ll lay out some information here so you can judge for yourself. 

What is the difference between omnivorous, vegetarian, and vegan diets?

An omnivore eats everything from meat, poultry, fowl, seafood, vegetables, fruits, and animal by-products like dairy, eggs, and honey. They often do not have any dietary restrictions unless they have food allergies or sensitivities. 

A vegetarian does not eat animals but may still eat animal by-products such as eggs or dairy. There are different types of vegetarian diets. See my post on Is A Plant-Based Diet sustainable?, where I lay out more specific details on various types of vegetarianism. 

A vegan does not consume any animals or foods made by animals. They solely rely on plants and plant-derived products for their nutrition (i.e., non-dairy products, meat substitutes, etc.). A person who follows a vegan lifestyle may also avoid purchasing items made from animals like leather. 

How do omnivore, vegetarian, and vegan diets influence your health?

Many people believe that plant-based diets or vegetarian and vegan diets are best for achieving optimal health and longevity. Is that true? 

A research review comparing plant-based diets to diets including small amounts of red meat found that there is a reduced risk of coronary heart disease (CHD) and type 2 diabetes (T2DM) for all dietary patterns that limit meat intake. While the highest reduction in CHD was seen in pescetarians (vegetarians that eat fish but no meat) and lacto-ovo vegetarians, occasional meat-eaters (those who ate red meat < 1 time per week) still saw a reduction in CHD when compared to regular meat-eaters (those who ate red meat > 1 time per week) (1,2). However, there is limited evidence that following a vegetarian or vegan diet helps with cancer prevention (1,2,3,4). Another study stated that a very low meat intake of less than once a week could be linked to longevity, but it is not a guarantee for living longer (5). Epidemiologic studies consistently show that mortality rates are similar to vegetarians and occasional meat-eaters (4). So, the jury is still out on whether you will live longer on a vegetarian or vegan diet. 

Specifically, high consumption of processed meat (i.e., cured meats like cold cuts, hot dogs, sausage, and bacon) has been associated with both a higher risk of developing CHD, cancer, and T2DM and mortality (1). Consuming animal protein closest to its original form is likely the better choice for health reasons. For example, pork chops instead of bacon or roasted turkey instead of deli turkey. 

Bottom line: Omnivore, vegetarian, and vegan diets are all good choices for health. If we want to improve our health, limiting the frequency of eating processed meat is recommended. That DOES NOT mean cutting out processed meat altogether. Instead, we should consider other options for protein like fish, eggs, and soy, and remember to include the other food groups into our meals - fruits, vegetables, and grains.

How do omnivore, vegetarian, and vegan diets influence our environment?

Putting health aside, is eating more plant-based better for our planet? Meat production is a large source of methane emission, which contributes to global warming. Because agriculture requires using a lot of freshwater, meat production located in water-stressed areas can make it harder to maintain the local ecosystems. Meat production can also affect the biodiversity of the land around it. (6). According to this New York Times article on making good climate choices, eating a vegetarian diet is one of the most meaningful ways we can personally cut down on emissions.

Bottom line: Similar to health, reducing meat consumption can benefit the health of our environment.

Takeaway Thoughts

A vegetarian or vegan diet is healthful but not the most optimal diet.

Studies have shown that omnivores can experience the same health benefits when consuming a balanced diet. So if you enjoy eating meat, poultry, and seafood, please continue. 

A balanced way of eating applies to everyone.

Eating a varied diet that includes adequate protein. fruits, vegetables, and whole grains will provide us with the essential nutrients we need to live well. Understand that consuming a vegetarian and vegan diet requires more careful planning to get adequate amounts of all essential nutrients. 

If you want to reduce the frequency of consuming animal protein, you do not have to become or label yourself vegetarian or vegan.

You can just be more plant-forward. Plus, these labels tend to be more for other people than yourself.

Choose how you eat based on your values.

Our way of eating does affect our planet. So if you are an omnivore who enjoys eating meat, ask yourself what realistic changes can you make to reduce your carbon footprint. Eating less meat than you do now can be impactful. 

Allow yourself to be flexible and honest when considering adopting new dietary patterns.

All-or-nothing approaches usually do not work very well because they constrain us to a small box with limited options. Life is about exploring, learning, and growth, and we should apply these principles to our relationship with food.

References

McEvoy, C, Temple, N, & Woodside, J, 2012, ‘Vegetarian diets, low-meat diets and health: A review’, Public Health Nutrition, vol. 15, no. 12, pp. 2287-2294.

Key, TJ, Fraser, GE, Thorogood, M, Appleby, PN, Beral, V, Reeves, G, Burr, ML, Chang-Claude, J, Frentzel-Beyme, R, Kuzma, JW, Mann, J, McPherson, K, 1999, ‘Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies’, The American Journal of Clinical Nutrition, vol. 70, no. 3, pp. 516s–524s

Ginter, E, 2008, ‘Vegetarian diets, chronic diseases and longevity’, Bratisl Lek Listy, vol. 109, no. 10, pp. 463-466.

Norman, K, Klaus, S, 2020, ‘Veganism, aging and longevity: new insight into old concepts’, Clinical Nutrition and Metabolic Care, vol. 23, no. 2, pp. 145-150.

Singh, PN, Sabaté, J, & Fraser, GE, 2003, ‘Does low meat consumption increase life expectancy in humans?’, The American Journal of Clinical Nutrition, vol. 78, no. 3, pp. 526S–532S

Godfray, HCJ, Aveyard, P, Garnett, T, Hall, JW, Key, TJ, Lormier J, Pierrehumbert, RT, Scarborough P, Springmann, M, Jebb, SA, 2018, ‘Meat consumption, health, and the environment’, Science, vol. 361, no. 6399.