The common idea that 1 pound of fat is equal to 3,500 calories most likely comes from original research in the late 1950's on the effects of fasting in obese individuals. Well, it stuck, and is the basis for our current, simple prescriptions for weight loss.
The subsequent rule, then, is to expend, 'burn', and/or reduce intake of 3,500 calories to lose a pound of fat. Commonly, this deficit is accomplished by expending and/or cutting 500 Calories per day for 1 week.
Could fat loss really be that simple?
Yes and no.
Yes, because quantity of calories matter. It is very difficult, if not impossible, to gain weight while in a caloric deficit.
No, because it is not that simple. Weight loss is not the same fat loss, calories are complex and enigmatic, and there are too many factors involved. Two people could eat the same number of calories, creating the same 500 calorie deficit between what they need and actually bring in; yet one loses 1 pound of fat and the other does not.
A very cool thesis was just published that put the 3,500-calorie myth to the test.
The author reviewed 43 different research articles to determine the caloric deficits required for a pound of weight loss and fat loss.
Some key findings:
- The number of calories required for producing one pound of weight loss varied considerably. A pound of fat was not simply 3,500 calories.
- The quality of the food mattered, with weight loss being dependent on where the dietary calories came from – different fats, carbohydrates, and protein. This finding supports that the best way to control the 'quantity' or amount of calories eaten is by improving the 'quality' of the food you eat.
- The best estimate came from a study in 1991, where the researchers extracted human fat samples. They calculated a pound of fat was equivalent to 4,423.90 calories.
Is a pound of fat equal to 3,500 calories? Probably not.
In the end, our focus should not be on arguing on the exact calories that equal one pound of fat. Rather, our efforts should be put into the ways we control calories; our forks and feet.
- Use your fork to improve the 'quality' of food you eat, which will subsequently control the 'quantity' of calories. As Michael Pollan simply states, "Eat food. Not too much. Mostly plants." See here for more details.
- Use your feet to lead an active overall lifestyle, which includes both physical activity and exercise. Aim for at least 150 minutes of moderate intensity physical activity, equivalent to a brisk walk, each week. Try to get at least 30 minutes each day, and limit how much you sit each day. See here for more details.