• Krista Smith, FNTP

Why the Calorie Hypothesis Is Flawed

Updated: Jul 10, 2018

I’m sure you’ve all heard this statement. “In order to lose weight, you need to eat less and move more.”

Logically, it seems to make some sense. People have been following this advice. They religiously exercise, consume less food and the surprising result happens. Nothing changes. What the heck?!

Humans are more than a simple math equation. Our bodies are complex with interconnected chemical and biological processes happening at all times. Keeping us alive is the key goal of all our systems and homeostasis is constantly being achieved. Simply consuming less while exercising more actually has some serious metabolic effects and this causes us to at best maintain weight.

Think about it. What happens when you finish a strenuous workout, especially when weight training? You get hungry, of course. You’ve put in a lot of work and your body needs energy to replace what was lost in catabolizing muscle (breakdown). It’s dehydrated, craving amino acids, minerals, perhaps glucose and fat in order to bring your body back to balance. Muscle is expensive, heavy and needs constant maintenance in order to build and repair. Makes sense, right?

What if you then don’t eat enough?

Over time, when we attempt to drastically restrict calories in this scenario, our body does the opposite of what we want in order to preserve energy to function. Our metabolism SLOWS down. When you consider that our body’s primary goal is to stay alive, it is clear why. Energy conservation. As Jason Fung likes to say, “Your body isn’t stupid.” Nature would not design your body to suddenly speed up and zap all the potential fuel when it is perceived to be in a famine situation. In fact, you’ll even begin to shuttle more glucose into the fat cells as the body prepares for the future. As far as your physiology goes, there could be another famine around the corner.

When you consider it in evolutionary perspective, people hunted and gathered food. This took energy and effort, sometimes for several days. After all that energy expenditure, they were rewarded with the kill.

When food was scarce, they did little work (now known as exercise) and expended less energy. Walking in search of it, sure, but not something intense like running around because if they did that, they would surely deplete their bodies and die. Even without consciously doing something about it, their bodies burned less energy when they weren’t active to compensate for the higher energy burn when they were more active.

Sure, if you eat too much for an extended period of time, you will begin to gain weight. But according to Gary Taubes (and many others), this fails to explain why the weight is gained. Calories are not a tightly controlled variable, otherwise we would gain weight simply because we ate 500 excess calories. Studies have shown that it can be difficult to gain weight by simply increasing calories and even if weight gain is achieved, the body will ramp up the metabolism to strive to go back to its baseline. Check out one of the studies Dr. Fung cites here.

What happens if you overeat?

When you overeat, your body needs time to process your meal. Oftentimes, people overeat at one meal, then continue to eat throughout the day. This doesn’t allow for your body to rest and digest and leads to a backlog (so to speak) of food. As Gary Taubes so eloquently states in his book, “We don’t get fat because we overeat. We overeat because we’re getting fat.” (pg. 105)

We haven’t even mentioned the main culprit in this simplified explanation. Insulin.

Food spikes glucose which tells your pancreas to produce insulin. Insulin is your body’s storage hormone. When glucose increases, insulin increases as a response to clear your bloodstream of all the sugar floating around. You need insulin because this response is what keeps you alive. Foods like starchy, refined carbohydrates and sugar, spike insulin far more than others. When you consistently eat a lot of them, your blood sugar stays high so your insulin also stays high. Over time, this behavior leads to more devastating effects like type 2 diabetes because your cells no longer respond to insulin’s request to get the glucose into the cell. Obesity occurs when this glucose is then converted to fat and stored in every location possible: the liver, the muscles, the fat cells, etc.

In the context of the calories in, calories out hypothesis, you could eat a ton of high carb foods and gain poor nutrition as a result. Simply eating less of these same foods is not the solution, because again, you are still spiking your insulin. Could you eat tons of chicken and broccoli? Likely not, because the protein and fiber will satiate you long before you could eat the caloric equivalent of, say, a cake.

In his book, The Calorie Myth, Jonathan Bailor explores the topic of the calorie hypothesis and discusses all the ways we are misinformed about how the body works. He states “Body fat storage is not caused by eating a lot of food. Body-fat storage is a response to eating food that causes us to have more glucose in the bloodstream than we can use at one time.” (pg.70)

You can’t out-exercise a bad diet. In fact, certain types of exercise could work against you.

It seems like some people are naturally thin. They eat crappy food all the time and never gain a pound. (Yes, I too am in awe of those people). Their metabolism is working really well for them and their bodies are naturally hardwired to partition out energy in a certain way. Another point to mention is that just because people are thin, doesn’t mean they are healthy. There could easily be a ton of damage internally that we just don’t see. Perhaps they are suffering from type 1 diabetes (in which the pancreas does not produce insulin), an autoimmune condition, improper nutrient absorption…you get the point.

The takeaway in all this is that the simple idea that burning more calories than you consume is not the key to making you lose weight and keep it off in the long term.


Targeting the root cause of the weight issue is paramount. Hormones are responsible for deciding where we gain weight and how its distributed. Eating a whole-food, nutrient-dense diet is just one piece in the weight loss puzzle. Other factors such as digestion, blood sugar balance (more hormones!), hydration also need to be addressed. Consulting with a qualified nutritional therapist or a functional medicine practitioner is a great way to get started.

I’ve listed a few of my information sources (find many of the books through my Amazon affiliate links below) which also offer some solutions if you’d like to learn more.


The Calorie Myth by Jonathan Bailor

Primal Blueprint by Mark Sisson

Why We Get Fat (and what to do about it) by Gary Taubes

The Obesity Code by Dr. Jason Fung

The Complete Guide to Fasting by Dr. Jason Fung and Jimmy Moore

The Keto Cure by Adam Nally and Jimmy Moore



Palmdale, CA



Krista Smith
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Nutritional Therapy Practitioner


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