The theory of protein combining became popular in the 1970s and has since experienced a resurgence in the health food industry.
Significant amounts of protein are promoted as a necessary component of every meal. In fact, the Paleo and Atkins diets are founded on the concept.
Advertisements abound in all forms of media to tell you to eat more protein to be strong, lean, and healthy.
The idea is that you must combine several different protein sources at every meal in order to take in all of the 20 amino acids your body uses to synthesize proteins. The concept also stresses animal protein as an essential component of each meal.
This theory has since been disproven as a healthful method of eating and here’s why.
The Myth Of Protein Combining
Of the 20 amino acids that build proteins necessary to grow, sustain muscle, and provide energy, 11 are essential. That is, you must take them in as food. In contrast, the body makes it on its own “non-essential” amino acids. Theoretically, you only really need to eat essential amino acids.
If the body had to rely on conscious eating decisions at every meal to incorporate every essential nutrient to survive, you’d never stop eating. Worse yet, the body would begin to deteriorate if you stopped.
We’re way more efficient and intelligent than that.
If there’s an excess of a particular nutrient, the body will either store it or eliminate it. If there’s not enough, the body will adjust to compensate and you might crave a particular food to satisfy its needs.
Consider cultures that live in strict accordance with the seasons, eating mostly plants in the summer and meat in the winter. While this is an extreme that most in the First World don’t experience, the example is nonetheless demonstrative that nutrient synthesis is an on-going process, not a meal-by-meal endeavor.
Too Much Protein is Not Healthy
Our bodies are built to thrive on a wide variety of foods, with no particular stress on any group. We need the vitamins, minerals, and phytonutrients from different food groups to thrive.
Currently, the U.S. recommended daily amount of protein is 0.36 grams per pound of body weight or 0.80 grams per kilogram. So, a 120-pound woman should eat around 43 grams a day and a 160-pound man, 57 grams.
Another guideline published by the World Health Organization recommends that both women and men eat 5% of their daily calories from protein (6% for pregnant or lactating women). Eating too much animal protein on a regular basis can lead to kidney dysfunction, gout, weight gain, and a number of other health problems.
In fact, meat and animal products aren’t the only viable sources of protein.
Plant Protein Is Complete Protein
The very foundation of the food chain is made up of plants. It’s unreasonable to believe that we can’t get the amino acids we need unless we eat other animals. In fact, the opposite is true.
“Overall it can be concluded that mixtures of plant proteins can serve as a complete and well-balanced source of amino acids that effectively meet human physiological requirements,” according to a review by the American Journal of Clinical Nutrition (1).
In a letter to the American Heart Association Science Advisory, John McDougall, MD—a vegetarian nutrition expert and best-selling author—blasts the protein misinformation promoted by medical sources:
“A vegetarian diet based on any single one or combination of these unprocessed starches (eg, rice, corn, potatoes, beans), with the addition of vegetables and fruits, supplies all the protein, amino acids, essential fats, minerals, and vitamins (with the exception of vitamin B12) necessary for excellent health. To wrongly suggest that people need to eat animal protein for nutrients will encourage them to add foods that are known to contribute to heart disease, diabetes, obesity, and many forms of cancer, to name just a few common problems.” (2)
The Body Knows What It Needs
When you eat, food is digested and absorbed by cells according to their function and need. “Pools” of free amino acids float inside cells, a product of the last several meals you ate, waiting to be combined with the remaining contingent of the 20 amino acids to be synthesized into whatever protein is needed, when it’s needed, where it’s needed.
A study of amino acid activity after a protein-rich versus a protein-free meal reported a not-surprising result:
“We observed a fall in concentration of most essential and some non-essential amino acids in plasma after the protein-free meal, whereas the protein-rich meal had the opposite effect… In addition, our results demonstrate that a protein-free meal and a protein-rich meal with identical non-protein energy content elicit opposite effects on the essential amino acids not only in plasma but also in muscle intracellular water.” (3)
With the 2 meals’ caloric content equal, cells in blood and muscle dipped into the pools to get the amino acids they needed when protein wasn’t there from food.
Eating well isn’t complicated. A diet of an extensive variety of plants contains virtually every nutrient your body needs, including protein. So forget about protein combining and diversify your diet.