If you consume a high-fat, low-carb diet, you will burn a lot of fat, because of course your carb intake is low and insulin secretion which is related to less carb intake will also be low.

which increases the rate of lipolysis and fat oxidation (burning).

That’s why your friend on the keto diet tells you it’s the best diet ever—because you’re always burning fat. That is absolutely true.

Yes, you’re burning a lot of fat, because you’re eating a lot of fat. You’re also simultaneously storing more fat (in case you eat more fat than your required daily energy intake). Your net fat balance (fat stored — fat oxidized — aka “burned”) is what will determine the overall loss of body fat.

Fat Balance = Fat Storage – Fat Burning

If Fat Storage is greater than Fat Burning = Weight Gain (Energy surplus)

If Fat Burning is greater than Fat Storage = Weight Loss (Energy Deficit)

If Fat Storage= Fat Burning= No Weight Change ( Energy Balance )

I realize your head is probably spinning a bit here.

What is important to know is that as carb intake rises, fat burning goes down and carb Storage goes up. As fat intake rises, carb Storage goes down and fat Burning goes up.

Same deal for fat storage: as carbohydrate Food intake goes up and fat intake goes down, you store less fat into Fat Cells.

As fat intake goes up and carbohydrate intake goes down, you store more fat in Fat Cells

It means the body is extremely flexible in the fuels it can use, and it will base its preference on what it’s exposed to. Some might find it reasonable to suggest that a low-fat diet is probably better than a low-carb diet from a physiological perspective because you store less total fat.

In reality, however, it’s not the rates of fat Burning, carb oxidation, or fat storage that tell the story of obesity. It’s the rate of fat burning versus the rate of fat storage, and this is determined by overall energy balance—or calories in versus calories out (CICO)

Extremists from both the low-carb and low-fat groups will try to convince people that the “calories in, calories out” (CICO) model of obesity is old-fashioned and has been disproven, but were going to carefully and systematically explain that erroneous hypothesis.

I want to be clear: different diets equal in energy/calories can have different effects on fat loss based on their macronutrient compositions, as we will discuss later, but that does not invalidate energy balance.

It simply means these diets affect energy output in some way. To understand why energy balance matters, we first need to explain the components that makeup “calories in” and “calories out.”

“Calories in” is exactly what it sounds like. This side of the energy balance equation is simple; how many calories did you eat in a day?

The “calories out” side of the energy balance equation are more complicated. “Calories out” is also known as your “Total Daily Energy Expenditure” (TDEE) and consists of 4 basic components:

1. Basal Metabolic Rate 2. Non-Exercise Adaptive Thermogenesis (NEAT) and Non-Exercise Physical Activity (NEPA) 3. Exercise activity (EA) 4. Thermic Effect of Food (TEF).

Basal Metabolic Rate (BMR) — The major component of your TDEE is your basal metabolic rate (BMR). Your BMR accounts for approximately 60% of your TDEE and is the amount of energy your body requires to run basic processes and “keep the lights on,” so to speak.

A more simple name might be “existence calories.” Still, even though this is a baseline to keep you alive, for most people it’s the major determinant of your TDEE unless you do a lot of activity, in which case it may be a smaller overall contributor to your daily TDEE.

How to Calculate BMR

Some commonly used synonyms of BMR are resting metabolic rate (RMR) and resting energy expenditure (REE); however, these terms have slightly different definitions.

Non-exercise activity thermogenesis (NEAT) and Non-exercise physical activity (NEPA) —

NEAT is the amount of energy you spend doing unconscious little movements throughout the day that aren’t actually exercised. These include typing on the keyboard, talking, fidgeting, wiggling your toes, etc.

NEPA refers to walking, standing, and any voluntary, non-exercise activity. This is actually the most adaptive component of metabolism, and it increases significantly during a caloric surplus and decreases significantly during a deficit.

Everyone handles the deficit differently. Sometimes even a small deficit renders you into being as inactive, but your NEAT still goes down, in which case, some people consciously increase their NEPA to offset the stillness of their metabolic adaptation.

NEAT is often used interchangeably with NEPA (non-exercise physical activity), though the main difference is whether we are conscious of the activity or not. For our purposes—and in the interest of not being pedantic—we will just refer to it as NEAT.

Thermic Effect of Food (TEF) — As weird as it sounds, there is also a thermic effect of food, meaning that it costs you energy to extract energy from the food you eat every day.

Different foods require varying amounts of energy to be processed and digested. Generally speaking, foods higher in fiber and protein have a higher TEF.

Exercise Activity – This is exactly what it sounds like. When you exercise, you expend calories. How much you expend depends on the duration and intensity of the exercise performed.

So when we get to the point where it’s time to calculate these equations, you have to take all of these into account. If all this looked like an equation, it would be:

TDEE = BMR + NEAT + Exercise +TEF

Looks simple right? It is, but then again it isn’t. Your TDEE can vary from day to day depending upon your activity, food intake, and a host of other factors.

So attempting to pinpoint a specific daily number is going to be difficult, but it doesn’t invalidate energy balance. It just means that the “calories out” side of the equation will have a certain error margin from day to day, but as we’ll discuss later, we can get pretty close.

Several groups of diet fanatics including hardcore clean eaters, keto diet fanatics, hard-line vegans, and a host of others have attempted to discredit the CICO model of fat loss and gain as outdated.

One of the major arguments many of these

groups make is that CICO is based on the first law of thermodynamics, which only applies to a closed system.

The first law of thermodynamics states that energy cannot be created or destroyed, only transferred. This applies to CICO because the energy you put into the system (your body) cannot just disappear.

It has to be used somewhere, but it doesn’t necessarily mean it’s conserved in your body since it isn’t a closed system. Indeed, you are not a bomb calorimeter (a device used to determine the energy content of compounds, including protein, carbs, and fats).

All of the energy you take in is not perfectly conserved in the body. Your body can dissipate quite a bit of energy as heat through the process of adaptive thermogenesis. What CICO critics don’t realize is that dissipation of energy is already accounted for in the “calories out” side of the equation, since NEAT includes this dissipation of energy.

So while energy is not perfectly conserved in the human body, our calculations already account for this fact.

Further, while the human body is not a closed system, the various components of “calories out” (TDEE) already take into account that the human body is an open system—making this argument a strawman.

So if you eat 2000 calories, something happens to them. They won’t all wind up as ATP or stored, and some will be wasted as heat through the process of thermogenesis, but this doesn’t invalidate CICO. In fact, it supports it.

This also means that if any diet were superior to another diet, it would need to affect one of the components of TDEE in a meaningful way and cause an increase in caloric expenditure compared to other calorie-equated diets.

For example, if a specific diet increased TDEE by 300 kcal per day, that would improve fat loss due to increased expenditure, or “calories out.” If a diet also caused a shift to favoring increased weight loss from fat tissue versus lean body mass, that would be an additional benefit.

Any potential benefit of a diet on energy expenditure can be explained based on TDEE = BMR + NEAT + EA + TEF.

Numerous metabolic ward studies support these findings, demonstrating that when calories and protein are equated, weight loss is the same.*2 *3 *4

Metabolic ward studies are important because they are extremely tightly controlled. The patients are provided their meals by the researchers, and the researchers place them in a room where they can measure their TDEE based on a few fancy techniques.

Some of the purported superior fat loss effects of various diets, such as the ketogenic diet, can actually be traced back to the fact that some people are more satiated by a ketogenic diet and simply eat fewer total calories.

to be continued …

End of Part 8

*2 “Energy expenditure and body composition changes after … – NCBI – NIH.” 6 Jul. 2016, https://www. ncbi.nlm.nih.gov/pubmed/27385608. Accessed 21 Aug. 2018.

*3 “Metabolic and behavioral effects of a high-sucrose diet … – NCBI – NIH.” https://www.ncbi.nlm.nih. gov/pubmed/9094871. Accessed 21 Aug. 2018.

*4 “Metabolic effects of very low calorie weight reduction diets. – NCBI – NIH.” https://www.ncbi.nlm. nih.gov/pmc/articles/PMC425077/. Accessed 21 Aug. 2018.