When I consider what the healthiest diet is for us, I think biologically. To fully understand current human biology, it helps to understand our evolutionary biology. Daniel Lieberman, professor of evolutionary biology at Harvard has distilled this complex subject in his 2014 book, The Story of the Human Body. He traces our evolution from chimpanzees and bonobos five million years ago through the ages of prehuman species, numerous human species, to homo sapiens up to 300,000 years ago. Throughout our evolution, we adapted to various diets based on geography and survival, dependent on food availability. Lieberman makes it clear that human survival depended on the consumption of both animal and plant foods, that is, as omnivores. The brains and digestive tracts developed on an omnivore diet.

I have strict vegan patients who only eat plant-based foods without dairy, eggs, meat or fish. I also have a few patients who are strict carnivores and only eat animal foods. Both of these restricted diets have their potential problems. To survive and be healthy, we must eat the three macronutrients: carbohydrates, protein and fat, and we must consume micronutrients: vitamins and minerals. Of the macronutrients, the most critical is protein of which our body is largely made. Carbohydrates and fat are foods that give us energy.

Proteins are made from amino acids. Our body cannot manufacture nine of them and we must get them from foods. Foods that have all nine of these essential amino acids are called complete protein foods and mostly come from animal sources such as meat, fish, eggs and dairy. People on an exclusively plant-based diet can get all nine of the essential amino acids through combinations of quinoa, soybeans (edamame and tofu), buckwheat, chia seeds, pistachios and amaranth. These are excellent plant sources of the essential amino acids and understanding the effective combinations is important.

There are also critical omega 3 fatty acids that we must eat to survive. Most of these come from animal sources, oily fish and krill. However, flaxseeds, chia seeds, walnuts and soybeans are additional non-animal sources. Any person on a plant-based diet exclusively knows the need for supplemental vitamin B12 which is only present in animal foods; nutritional yeast is fortified with B12 and a good plant-based source. Less well known is an increased risk for bone loss and early development of osteoporosis. Supplementation of vitamin D3 with vitamin K2 is essential.

Harvard-trained nutritional psychiatrist Georgia Ede, author of Change Your Diet, Change Your Mind (2024), emphasizes the importance of meat, fish and eggs for mental health, especially in children and adolescents.

Animal foods from industrial concentrated food operations (CAFOs) are not recommended and should be avoided to limit exposure to hormones, antibiotics and toxins. The same is true for all ultra-processed foods.

Whatever diet a person chooses to eat, attention must be paid to getting enough protein, including essential amino acids, carbohydrates for short-term energy and fats for long-term energy.

We truly are what we eat and our gut microbiome must be well fed for our intestinal health, mental health and immune system to thrive.

Dr. Scherger is the founder of Restore Health Disease Reversal in Indian Wells, a clinic dedicated to weight loss and reversing chronic medical conditions. To schedule a consultation, call (760) 898.9663 or visit www.restorehealth.me.