How Much Carbohydrate Do We Need?
A rarely addressed question
By Steve Anthony
I’ve touched on this is other articles, but felt it deserved an article of its own.
There are three macronutrients that are typically found in diets (and I’m using that term broadly) around the world: Protein, Fat and Carbohydrate.
The current dietary recommendations coming from the US Department of Agriculture are very agriculture-heavy. As such, the USDA guidelines are very carbohydrate-heavy: 6 to 11 servings of grains (bread, cereal, pasta and rice) along with 3–5 servings of vegetables and 2–4 servings of fruit. That’s up to 20 servings, per day, of food containing carbohydrate — as much as 65% of one’s daily caloric intake.
Consider Bob — a 35-year-old male, 6 feet tall, 180 pounds, who does light exercise: According to the first BMR calculator I found on the internet, this guy should be eating about 2,500 calories a day. If he follows the USDA guidelines, he should be shooting for about 1,625 calories from carbohydrate. At 4 calories per gram, that’s about 406 grams of carbohydrate per day.
How does that compare with the number of grams we need to eat to survive? Turns out that for Bob, 406 grams of carbohydrate is 406 grams more than he needs to eat. That’s right, Bob doesn’t need to eat ANY carbohydrate to live a long, natural life. And it turns out that none of us humans need to eat a single gram of carbohydrate to survive.
I know what you are thinking — this can’t be true, right? Well, it IS true.
There are certain nutrient components we need to eat to survive. In the field of Nutrition, the nutrients we need to eat are referred to as “essential.”
We need to eat fat to get the 2 essential fatty acids our body needs to live (omega-3 and omega-6). We need to eat protein to get the 9 essential amino acids our body needs to live. Interestingly, our body needs 20 different amino acids to live — but we only need to eat a specific set of 9 because the body can make the other 11 out of those 9.
There is no such thing as “essential” carbohydrate. Yes — our body does need some glucose, and our body breaks down any carbohydrate we eat into glucose. But we don’t need all that much glucose, and our liver can synthesize all we need. And our liver makes the glucose we need from body fat. Seems like that could be useful!
If we eat a lot of carbohydrate, however, they liver is prevented from using fat to make glucose — and basically, it doesn’t need to because if you eat a lot of carbohydrate, you end up with a lot of glucose in your system.
But you ask, don’t we get most of our energy from glucose? The answer is yes — if you eat a lot of carbohydrate. But if you don’t eat a lot of carbohydrate, your liver (it’s a great name for the organ that does so much to keep us alive!) will create ketone bodies out of, you guessed it, your body fat.
How cool is that! We don’t need to eat any carbohydrate — our body can make all the glucose and alternative fuel it needs from our body fat.
But wait, if we don’t need any carbohydrate, why does the USDA recommend 65% of our calories take the form of carbohydrate? To me, the answer is simple: The US Department of Agriculture has a mission — to promote agricultural products in the US and worldwide. Is it any wonder that the US promotes its dietary guidelines worldwide?
And if you look at agriculture production in the US, about 70% of our agriculture is grains, 22% is vegetables and 7% fruit. That kind of lines up with the servings per day recommended by the USDA. So the old Food Pyramid, which is now called Choose My Plate (but makes the same recommendations), is more of a marketing piece than a health recommendation — kind of like how the Diamond Industry suggest men spend two months’ pay for an engagement ring, or the Milk Industry asking you if you’ve Got Milk.
But so what? We are told to eat 65% of our calories as carbohydrate when we really don’t need any — what could go wrong? If you look at the upward trend in incidence of being obese, and when the USDA guidelines were released, you could conclude A LOT could go wrong.
As I mentioned above, when you eat a lot of carbohydrate, you end up with a lot of glucose in your system. When it’s in your blood, your pancreas secretes insulin to “manage” it. The more carbohydrate you eat, the more glucose you have to be managed; the more glucose that has to be managed, the more insulin is pumped into your blood. If insulin levels in your blood get too high, your liver stops creating alternative fuel from fat — instead, insulin stores the excess glucose as body fat. Thanks a lot insulin!
Don’t blame insulin. It’s just trying to save you from the danger of a blood glucose level that’s too high. But you can see how too much carbohydrate can, theoretically, cause people to gain weight; the graph above shows that this theory could be right.
References used in writing this article:
Obesity Data: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics and Prevalence of obesity among adults and youth: United States, 2015–2016 (NSCH Data Brief №288). Hyattsville, MD: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics.
Dietary Guidelines for Americans, Eighth Edition, 2015–2020 https://www.dietaryguidelines.gov/sites/default/files/2019-05/2015-2020_Dietary_Guidelines.pdf
Lehninger, A., Nelson, D. and Cox, M. Principles of Biochemistry
This article is intended for informational and educational purposes only. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment. You should not rely on this information as a substitute for, or a replacement of, professional medical advice, diagnosis or treatment. This article is not intended to prevent, diagnose or cure any medical condition, nor should it be construed as advice on medical nutrition. All viewers of this content should consult their physicians before beginning any nutrition, supplement or lifestyle program.