It’s unthinkable, right?
Who would ever have imagined that two diets with an identical calorie count – high-carb and ultralow carb – would have such vastly difering results in terms of fat loss and muscle gain. After all, energy-in equals energy-out, and it all gets balanced in the end, regardless of when we train and when we eat. At least that’s what we’ve been told for decades.

To the “experts,” this is simply an exercise in the first law of thermodynamics, which states that energy is neither created nor destroyed. In other words, the total energy of the system must be the same, before and after which means that 500 calories of carbs will produce the same result as 500 calories of protein or fat.

The first law of thermodynamics, however, doesn’t mention anything about efficiency in terms of how the body converts this food into energy. It also tells us nothing about what happens if more or less of this energy is wasted depending on what types of macronutrients we’re taking in.

The second law of thermodynamics is more applicable to the human body, because it allows for the notion of efficiency. Efficiency is a measure of how much work you’re getting done based on the energy you’re putting in. A standard internal combustion engine the one  in your car is approximately 33% efficient. This means that about a third of the energy you’re putting in actually does work. You’re losing the rest of it in the form of heat.


This is essentially how your body works. When your diet consists of 60% carbs, your body wastes about two-thirds of the ingested energy as heat. Some of this helps hold our internal temperature constant, but the rest is lost in other ways. Research on efficiency and wasted heat shows that carbs lead the way in this department when they comprise 55% of the diet or greater. Carbs make you efcient. As you’ll soon see, that’s not what you want.

What happens, however, when we use a different type of fuel? Obviously, the efficiency levels would change, the fuel would burn in different ways, and you’d either increase or decrease your gas mileage. Add ethanol to a car, and your fuel economy decreases. Add other hydrocarbons, like anti-knocking agents, and it increases.

Try to transfer this logic to the human body, however, and most physique coaches’ eyes glaze over as though, in 2013, it’s still inconceivable that different ratios of macronutrients can cause diferent amounts of energy to be wasted in the human body. A calorie, after all, is still a calorie.

The body, however, disagrees, and it obeys the second law of thermodynamics. This means it varies in efficiency based on activity, hormonal status, and the type of fuel we provide. That’s why Wilbur Atwater, who introduced the 4-4-9 calorie values for carbs, protein, and fat, distinguished between physical fuel values and physiological fuel values.

The physical fuel value is the amount of energy you can get out of food by burning it with oxygen. You throw food in an oven, incinerate it, then record the total amount of heat released. The physiological fuel value is the amount of energy  an organism can derive from the fuel, which can be higher or lower than the physical fuel value.

It has been found that the human body, in a growth stage, can get more than 11 calories per gram out of fat significantly more than the 9 grams listed on most nutritional labels. This is because different activities require diferent enzymes or other molecules. Different or accelerated avenues of metabolization can produce different amounts of energy, and a calorie of fat is clearly not a calorie of fat. The same concept holds true for protein, as well, and these values don’t match up there, either. About 2% of your ingested calories of fat, 7% of carbs, and 30% of protein is wasted as heat whenever you eat.

If we take our 60% carb diet and invert it so a larger percentage of calories now comes from protein, two 2,000 calorie diets are possible: a high-carb version providing 1,850 physiological  calories, and a low-carb one that provides 1,700 (accounting for all the heat loss). By swapping things out, we cut 150 usable calories per day, even though we’re still consuming 2,000.

If you love food, but want to drop fat and build mass, being inefficient is a good thing. If you’re inefficient, you can eat more and actually drop fat. My diets, the Carb Nite Solution and Carb Back-Loading, manipulate this effect to make the human body as inefficient as possible at the right times. With CNS, the diet has been refined to where your body almost literally can’t store the carbs you’re taking in as fat. You work so hard trying to process them that it releases a ton of heat, you sweat like a faucet, and your vascularity goes through the ceiling. So stop counting calories and start worrying about your body’s efciency and inefficiency. It’s a law of physics, and I’ll take the advice of a physicist over an Internet diet guru any day of the week.