What Are Humans Supposed to Eat? The Ultimate Guide

When it comes to food, there’s a lot of confusion out there. Vegan, paleo, keto, vegetarian, low carb, high carb, fat-free, gluten-free – the list goes on and on. What are humans really supposed to eat? Let’s dive into the ultimate guide to find out.

What Did Our Ancestors Eat?

The first place to start when figuring out what humans are supposed to eat is to look at our ancestors. For most of our history as a species, we were hunter gatherers. We didn’t have access to modern agriculture or processed foods.

So what did our ancestors eat? Generally, they ate a diet that was high in protein and fat, and low in carbohydrates. Their diet consisted of:

  • Meat from wild animals
  • Fish and seafood
  • Eggs
  • Fruits and vegetables
  • Nuts and seeds

This is often referred to as a “paleo” diet, since it is similar to what our Paleolithic ancestors ate. However, it’s worth noting that our ancestors’ diets varied depending on where they lived and what was available to them.

Why Did Our Ancestors Eat This Way?

Our ancestors’ diet was high in protein and fat because these are the foods that helped them survive and thrive. Protein is necessary for rebuilding and repairing tissues and organs, and fat is necessary for energy and insulation. Carbohydrates, on the other hand, were not a reliable source of energy, since our ancestors did not have access to grains, which are high in carbs.

Fruits and vegetables were also important parts of our ancestors’ diets, as they provided vitamins and minerals that kept them healthy. Nuts and seeds were a good source of fat and protein, and were often stored for times when food was scarce.

What Do Modern Humans Eat?

Fast forward to the present day, and our diet looks very different from our ancestors’. We now have access to a wide variety of foods, including highly processed and fast foods. Our diets are often high in carbohydrates, and low in protein and fat.

According to the USDA, the typical American diet consists of:

  • 63% carbohydrates
  • 16% protein
  • 21% fat

This is a stark contrast to our ancestors’ diet, which was around 19-35% protein, 28-58% fat, and 22-40% carbohydrates (depending on location and season).

Why Has Our Diet Changed?

Our diet has changed for a variety of reasons. One factor is the rise of agriculture and modern food processing. Grains and other high-carb foods are now readily available, and are often heavily processed with added sugars and other additives.

We also have access to a wider variety of foods thanks to modern transportation and globalization. This has led to an increase in the consumption of fast food and highly processed snacks, which are often high in carbs and low in nutrients.

What Should Humans Eat?

Based on what we know about our ancestors’ diet, and the negative health effects of modern foods, many experts believe that humans should focus on a diet that is high in protein and fat, and low in carbohydrates.

What Types of Foods Should We Eat?

When it comes to specific foods, here are some guidelines:

  • Meat: Choose grass-fed, organic meats whenever possible. Avoid processed meats.
  • Fish and Seafood: Choose wild caught fish and seafood whenever possible. Avoid farmed fish, which may contain high levels of toxins.
  • Eggs: Choose free-range, organic eggs whenever possible.
  • Fruits and Vegetables: Choose organic, locally grown fruits and vegetables whenever possible. Aim to eat a variety of colors to get a wide range of vitamins and minerals.
  • Nuts and Seeds: Choose raw, unsalted nuts and seeds whenever possible.

In addition to these foods, it’s important to avoid processed foods and foods that contain added sugars and other additives. Focus on whole foods that are as close to their natural state as possible.

What About Grains and Other High-Carb Foods?

Sources of grains and other high-carb foods should be limited in a healthy human diet. While these foods provide energy, they are often heavily processed and can lead to spikes in blood sugar and insulin levels.

However, it’s possible to include some grains and other high-carb foods in a healthy diet. Some good options include:

  • Brown rice
  • Quinoa
  • Sweet potatoes
  • Beans and legumes

Just be sure to choose these foods in moderation, and avoid processed versions that contain added sugars and other additives.


In conclusion, humans are supposed to eat a diet that is high in protein and fat, and low in carbohydrates. This is similar to what our ancestors ate, and what many experts believe is the healthiest diet for humans.

By focusing on whole foods and avoiding processed foods and added sugars, we can help our bodies function optimally and avoid many of the negative health effects associated with modern diets.


1. Can humans survive on a vegetarian or vegan diet?

Yes, humans can survive on a vegetarian or vegan diet. However, it can be more challenging to get enough protein and certain vitamins and minerals on these types of diets, so careful attention to nutrient intake is important.

2. What about dairy? Should humans consume dairy products?

It depends on the individual. Some people can tolerate dairy products, while others are lactose intolerant or have other issues with dairy. If you do consume dairy, choose grass-fed, organic products whenever possible.

3. Is it okay to consume fast food and highly processed snacks in moderation?

While it’s not ideal to consume these types of foods, it’s okay to do so in moderation. The key is to focus on whole, nutrient-dense foods the majority of the time, and limit processed foods and added sugars.


1. Cordain, L., et al. (2005). Origins and evolution of the Western diet: Health implications for the 21st century. The American Journal of Clinical Nutrition, 81(2), 341-354.

2. Harvard School of Public Health. (n.d.). The nutrition source: Protein. Retrieved from https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/protein/

3. USDA. (2015-2020). Dietary guidelines for Americans. Retrieved from https://www.choosemyplate.gov/dietary-guidelines

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