I love the influx of big brain writers, thinkers and practitioners in the fitness and nutrition industry. Here's a great example:
Sorry big-box trainers and the equivalent ilk: the body obeys the 2nd law of thermodynamics as it does the 1st and therefore varies in efficiency based on activity, hormonal status and—by far the most important factor—the type of fuel we provide. That’s why Atwater, the father of the 4-4-9 calorie values for carbs, protein, and fat, respectively, distinguished between physical fuel values and physiological fuel values16.
In other words, the guy that identified calorie values by oxidizing macronutrients in a calorimeter knew from the beginning that there's always a difference in the potential energy in a fuel, and the actual energy delivered from a system after consumption.
The first, physical fuel values, is the amount of energy you can get out of food by burning it with oxygen, literally. You throw food in a fancy oven, incinerate then record the total amount of heat released—this is the physical fuel value.
The physiological value is the amount of energy the organism can derive from the fuel, which can be lower or higher. Fat, for example, depending on if the body is in a growth stage can get over 11 calories per gram out of fat17-21. That’s significantly more than the 9 listed on candy bar wrappers.
This is a consistent result of measurement. Clearly, even a calorie of fat is not a calorie of fat.
The physical and physiological fuel values don’t match up for protein either. It takes energy to process the food we eat, energy that’s wasted as heat known as the thermic effect of feeding (TEF). When you eat a meal, you warm up. It’s that simple. There’s an extensive amount of research on the subject: about 2% of the ingested calories of fat, 7% of carbs and 30% of protein is wasted as heat whenever you eat22.
Let’s stop for a second. This is well established fact. There’s no disagreement in the scientific community, amongst pop-diet writers, not even among medical professionals. Knowing this, you can calculate the difference in physiological fuel values between two identical diets. If you took a diet that is 60% carbohydrates, swapped it around so that a much larger percentage of the calories came from protein, you could create two different 2000 calorie diets, one that’s high-carb providing 1850 physiological calories (considering all the heat lost) and one that’s low-carb providing about 1700 physiological calories (even more heat loss). By shuffling things around, we cut 150 usable calories per day while still putting 2000 calories into our mouths.
Sorry big-box trainers and the equivalent ilk: the body obeys the 2nd law of thermodynamics as it does the 1st and therefore varies in efficiency based on activity, hormonal status and—by far the most important factor—the type of fuel we provide. That’s why Atwater, the father of the 4-4-9 calorie values for carbs, protein, and fat, respectively, distinguished between physical fuel values and physiological fuel values16.
In other words, the guy that identified calorie values by oxidizing macronutrients in a calorimeter knew from the beginning that there's always a difference in the potential energy in a fuel, and the actual energy delivered from a system after consumption.
The first, physical fuel values, is the amount of energy you can get out of food by burning it with oxygen, literally. You throw food in a fancy oven, incinerate then record the total amount of heat released—this is the physical fuel value.
The physiological value is the amount of energy the organism can derive from the fuel, which can be lower or higher. Fat, for example, depending on if the body is in a growth stage can get over 11 calories per gram out of fat17-21. That’s significantly more than the 9 listed on candy bar wrappers.
This is a consistent result of measurement. Clearly, even a calorie of fat is not a calorie of fat.
The physical and physiological fuel values don’t match up for protein either. It takes energy to process the food we eat, energy that’s wasted as heat known as the thermic effect of feeding (TEF). When you eat a meal, you warm up. It’s that simple. There’s an extensive amount of research on the subject: about 2% of the ingested calories of fat, 7% of carbs and 30% of protein is wasted as heat whenever you eat22.
Let’s stop for a second. This is well established fact. There’s no disagreement in the scientific community, amongst pop-diet writers, not even among medical professionals. Knowing this, you can calculate the difference in physiological fuel values between two identical diets. If you took a diet that is 60% carbohydrates, swapped it around so that a much larger percentage of the calories came from protein, you could create two different 2000 calorie diets, one that’s high-carb providing 1850 physiological calories (considering all the heat lost) and one that’s low-carb providing about 1700 physiological calories (even more heat loss). By shuffling things around, we cut 150 usable calories per day while still putting 2000 calories into our mouths.
Just another way to give the lie to the well meaning simpletons who say "a calorie is a calorie", which is true but completely meaningless.
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