I recently went to a dinner at a local steak house hosted by a referring physician. The group was all doctors, and they saw me order from the "vegan" menu. Quickly, the conversation shifted into a spirited debate amongst colleagues on the merits of plant-based diets.
.
A very common belief, which persists even in the medical community, is that vegans have nutritional deficiencies and consume too many unhealthy "carbs"
But what does the evidence say about plant-predominant diets?.
Let's tackle this question.
Carbs
Not all carbs are created equal. For example, a slice of white bread has 80 calories and 0.8 grams of fiber. A half cup of quinoa has 110 calories and 5 grams of fiber. Both are vegan, but each has a very different glycemic index: white bread is a processed food with high gylcemic index, quinoa is a whole food with low gylcemic index. Low fiber starches and sugar cause spikes in insulin and insulin-like-growth factor, which are detrimental to the lifespan of humans. Low fiber diets also cause bacterial imbalance in the colon, autoimmune disease, and cancer. If vegans substitute processed carbs for meat and dairy, they tend to gain weight and have problems with chronic disease
Fats
Many plant sources of fats (olives, avocados, nuts etc) have favorable nutritional profiles and promote healthy skin, nails, blood vessels, and immunity. Most animal sources of fat contain high amounts of pro-inflammatory precursors (arachadonic acid etc). Even when losing weight on a high protein, low carb diet (keto, atkins etc), people can develop chronic health problems, making it not advisable to follow these diets long-term. Certain animal sources of protein, such as egg white contain no fat at all, while others, such as wild-caught Alaskan salmon, contain high levels of "good" fats, similar to plants.
Protein
Consuming meat and dairy is a good way to increase protein intake. A majority of athletes and fitness competitors consume high amounts of animal protein during the "growth phase" of training. Methionine is an amino acid found in all types of proteins, but is in especially high concentrations in animal sources. It stimulates insulin-like-growth factor which helps build muscles and "bulk," which is great for growing adolescents and body-builders Unfortunately animal-derived protein long-term also promotes cancer growth and inflammation.
Micronutrients
Certain vitamins, like B-12 and Vitamin D may be low in plant based diets, but even normal diets have these deficiencies. A daily multivitamin can solve this issue. Other micronutrients such as polyphenols with robust anti-inflammatory properties are found only in fruits and vegetables.
The Verdict
An unhealthy diet is UNHEALTHY, whether it's vegan or keto or something in between. If you eat meat, try limiting the amount that you eat (2-3 times per week), and try to select from healthier options (certain fish). A plant predominant diet is healthiest, if done right. Just don't eat more sweets, or processed foods as a substitute. If trying to lose weight in the short term, limit carbohydrates and don't worry about cutting out the meat right away. If trying to build muscle and bulk, eat more protein and calories in general. However, if you are a normal weight adult looking to optimize healthy metabolism long-term, a plant-predominant, whole-food diet, is strongly supported by data
Chanu R. Dasari, MD
Always be true, and surround yourself with people who affirm your wellbeing. Find a doctor who will slow down and listen; find one who carefully considers your concerns; find one who cares.