How to know what to eat

plate of vegan food

The Why, What and How of Eating

Simply put, we need to eat because we need food and water to sustain us. Sustenance comes in the form of food and liquid (preferably water), where food provides energy and nutrients and water the lubrication the human body needs to function.

Throughout history, humans have tried to prove that we can survive without food. They have consistently failed as you can read about here. Given that most of us understand that food and water is essential for life, fundamental questions arise about their role. Why do we need food and water to survive? What exactly does food and water do in the body? How to we know which food to eat?

If you think there are clear, concise answers to these basic questions, there aren’t. These simple questions have spurned centuries of research by scientists, tens of thousands of books and “diets” that guide your understanding, a whole diet and supplement industry and untold numbers of food products and meal ideas designed to optimize your health – through food.

In this article, I am going to answer the questions: Why do we eat? Do we know what to eat? How do we know what to eat?

Why Eat Why Drink?

Let’s tackle this tackle question by looking first at water and then food.


We all agree that if you don’t eat or hydrate, you die. Between the two, you need water more than food. Water is the fluid or lubrication that allows your blood to circulate and distribute nutrients. It is a medium to remove toxic compounds and byproducts of metabolism (AKA eating) from your body. In short: poor blood flow and a growing toxic waste in your body means a very short life.


In a nutshell, the reason we eat is to provide the body with the energy needed to do its business. Food provides the energy the body needs to conduct its business where the business of the body includes breathing, moving, eating, blinking, storing energy for later use.

Think of food as a repository of calories (energy) and assorted nutrients like protein, fat, vitamins and minerals. Calories basically describe the amount of energy that can be extracted and utilized by your body from proteins, fats and carbohydrates.

Through a dazzling system of biological “engineering,” these complex nutrients are broken down into energy units called ATP or Adenosine Triphosphate. I call ATP the energy “currency” of the body, since it is required to fueling every biological cycle and system in the body the body.

Food is More Than Energy


Food is more than an energy repository, it’s also a rich deposit of nutrients in the form of vitamins and minerals.

Here’s a nutrition teamwork analogy. If you’re building a house, you need cement for the foundation and wood (sometimes steel) for the frame and rafters. Think of these materials as your protein, fat and carbs. To pour the cement and frame out the house, do the drywall, plumbing, electricity and cabinetry, you need workers. No workers, no house. It’s the same with vitamins and minerals. They are the construction site workers who are so essential to putting the different elements of the house together.

In the body, proteins, fats and carbohydrates cannot do their job without vitamins and minerals. Different jobs require different vitamins and minerals. You can read about these different jobs or “cycles” here.

Does Anyone Know WHAT To Eat?

If you want to get into a long discussion, ask people which foods are best for health. Take a scroll through social media posts to see what I mean. You quickly see that eating is both political and emotional these days.

Take the plant versus meat discussion. The vegan position is 100% plants, excluding any form of animal protein. This is often (but not always) an ethically informed choice with its roots in inhumane treatment of animals, even if those animals are grass-raised and finished on a small family farm.

How about the keto versus carbs discussion? Another opinion-driven heated conversation where a truce is rarely called. Intermittent fasting versus meals with small snacks anyone? Then there is the “my meal plan solution” versus yours, or my “six-week solution” versus the next one on the book shelf.

It is a quagmire where the nutrition noise is constant, and the public is left with no clear guidance.

Who Is Right?

Starting with the vegan position, they are 100% right in their advocacy of plants which provide perhaps the richest sources of nutrients and bioactives on the planet. Grass-fed protein advocates are also right in that the derived meat and dairy products (and select seafood) are an excellent source of critical nutrients, including the ready-to-use, active forms of omega-3 fatty acids: EPA and DHA.

If you are vegan with a gene variant that does not allow you to efficiently convert plant-based forms of the omega-3 (known as Alpha Linolenic Acid) into the active EPA and DHA forms, conceivably you can undermine your health no matter how many plants you eat.

what to eat

Do you KNOW……. what to eat?

The keto peeps are right in that a rich plant-centric diet accompanied by quality fat sources in lieu of carbs does work for some people, and very well. For others, a high fat low carb version of the ketogenic diet is frankly dangerous. Nowhere is this clearer than when someone is severely ill. Read more about keto and cancer here. Also cutting edge research combining diet and drug therapy for cancer in this brilliant interview with Siddhartha Mukherjee, M.D., Ph.D. Here we learn that ketogenic approaches do work in some cases as shown in research, but in others, a ketogenic diet can promote more tumors.

Advocates of Intermittent Fasting (IF) are correct in that the body responds beautifully to extended periods without meals or snacks. This is why the first meal of the day is a “break fast.” If intermittent fasting interests you, I recommend you follow the work of Dr Satchidananda Panda at the Salk Institute. Or listen him to him talk here.

Dr Panda has conducted extensive research on the role of IF in metabolic disorders, to include diabetes and obesity. Much of his work is centering on how IF can help reset the body’s natural clock (Circadian rhythm). When our circadian rhythm is disturbed through shift work, late nights, stress, screen time, metabolic disorders often follow resulting in diabetes and cardiovascular disease.

Who is right?

Genes Tell You WHAT To Eat And WHY

Genes determine your traits (blue eyes, curly hair etc.), but they also determine how your body responds to different foods, such as less carbs and more fat, or more Vitamin D. Genes override any diet formulation or even ethical approach to eating. They simply don’t have a dog in the fight and they can’t express an opinion either. You are born with them and like it or not, they have the final say over which food is right for you!

Food and nutrition guidance in the USA are often based on RDIs or Recommended Daily Intake values. RDIs guide school meal composition, food labeling, menu nutrition information and even hospital meal plans. While the RDIs provide guidance on optimal nutrient intake every day, they are based on population studies and are not individualized. This means that many of us will do fine with these recommendations, but the remainder of us need a different configuration. Why? Because our genes say so!

Getting personal

A diet high in saturated fat is a disaster for me. My gene picture clearly illustrates that I don’t package saturated fat, transport it, store it or use it well, AT ALL. Less is best. It makes me an olive oil versus coconut oil gal (which I love by the way). Butter, a dab here or there, but not my go to fat anymore. I can balance out my fat intake with foods rich in omega-3 fatty acids (Seafood, nuts, some dairy, eggs) to up my calories. The main thing is to steer around the saturates.

Gotta get choosy with carbs: The way my gene picture plays out, I don’t handle a heavy load of carbs either. Many of us don’t. If we look at mathematics, public health guidance recommends a carbohydrate intake ranging from 45 – 65% of total caloric intake. I am at the 45% or much less level.

Why? Because my genes line up in a way that places me at higher risk for glucose intolerance and sluggish insulin production. If I challenge my genes year after year with sugary foods and sweet baked goods, in the end my blood work will prove my genes right with elevated blood sugar and hyperinsulinemia. We see this over and over when we look at genomic profiles. Our genes NEVER lie.

I don’t need to eschew carbs, but I do need to shoot for the lower glycemic vegetables, berries, non-tropical fruit along with legumes to make up the carb component of my diet. These collectively ease the burden on insulin to handle the carbohydrate load.

Nutrients: This is where genomics is profound and takes a different track. Genomics tell us how well we “use” a nutrient depending on different systems in the body.

This has nothing to do with basic nutrition guidance, and everything to do with you, your body and how well it operates using nutrients. My genes don’t produce or use vitamin D well. They don’t produce the active form of an antioxidant, CoQ10, ubiquinol. They aren’t efficient producers of antioxidants that help me fight inflammation. I now take a vitamin D3/K2 supplement at a higher concentration than the RDI to optimize my vitamin D levels. I take an ubiquinol supplement because I cannot produce it from CoQ10. I focus on getting crucifers, berries and turmeric onto my plate as often as possible to support the sluggish genes that produce my antioxidants.

How do YOU know what to eat?

While some of the food and nutrition guidance available today, may seem whacky and faddish, some of the other trends such as Keto, Paleo and Intermittent Fasting actually have very relevant science to support them. The challenge is while these individual approaches may work for 70% of people, they simply don’t for others. Some folks drop weight like a rock while others do the same, but their triglycerides or LDL cholesterol soar. This means that regardless of how good the testimonies are, your body may respond differently. Your genes are the best confirmation of which food, how much and why.

All this being said, many of us don’t have personal genomic information at hand, so what do you do? This is precisely why I created The Genomic Kitchen and share wisdom through our blog and newsletters. Read more about our ingredient toolbox here. And be sure to sign up for our newsletter as well.