How Many Calories In A Pound Of Fat?

For those who count calories, the goal is usually to lose some excess fat. As nearly everyone knows, weight loss requires the use of a caloric deficit. By using less energy than you ingest, the body cannot help but lose weight. However, human metabolism is a complicated thing, even when its rules seem simple on the surface.

In this answer, we will attempt to find out how many calories are in a pound of fat. Obviously, the answer to this question is of great importance for those who want to get rid of their excess body fat. We will also tell you how you can benefit from this knowledge.

The Established Answer

The first person who attempted to answer this question in a definitive way was a scientist named Max Wishnofsky. His research paper on the subject was considered to be the best answer for many years. According to Wishnofsky, a pound of body fat contains approximately 3500 calories.

Although Wishnofsky’s hypothesis has been cited in literally thousands of scientific studies, modern researchers are now questioning whether or not these numbers are true. So, we have to ask ourselves: Is it wrong? Let’s consider the facts.

First of all, it is important to understand that Wishnofsky understood the existence of individual variation. In other words, he knew that the actual number of calories in a pound would vary from one case to another. Therefore, there is no perfect answer to this question. For instance, some research has found that genetics can play a role in the overall fat content of your body’s adipose tissue.

It is also important to understand that this a functional rule, not a technical one. The basic idea behind Wishnofskys’ research was to figure out how many calories a person must burn before losing a pound of body weight from fat. Thus, the “3500-calorie rule” has served as a useful dieting and exercise benchmark for a long time.

Is This Answer Correct?

Although the 3500-calorie rule is based on reality, it doesn’t reflect all the factors of human biology. There are several reasons why modern researchers say that you shouldn’t rely too heavily on this rule.

The first reason is the fact that the body does not use fat as its sole source of energy. When the body experiences an energy deficit, it will do everything in its power to fill that void. In doing so, it will burn not only fat but also muscle and other lean tissue.

You may have wondered what people mean when they talk about “burning fat.” Those people are talking about a biological process called Catabolysis, whereby the body begins to feed on tissues other than fat. However, here is where we run into an issue. Catabolysis only occurs when the body is totally depleted of other nutrients. This can take as long as two months to begin happening at a significant level. Therefore, this criticism is not particularly valid.

The average person will never experience levels of hunger that are severe enough to cause this problem. However, Catabolysis can also be caused by protein deficiency. Protein is the basic building block of all muscle tissue and the main component of your body’s muscle repair system. Therefore, a low-protein diet might cause this issue to become real and valid. Also, there is a small amount of muscle Catabolysis that can occur even if the body is not in a starvation state.

The second reason is the fact that the human body does not burn its calories at an even rate. Human metabolism can change in many ways as you lose weight, and its’ metabolic rate is unlikely to remain steady. This fact seems to be well-proven.

For instance, take a look at this study, in which researchers attempted to find an average resting metabolic rate that could be applied to all adults. After exhausting every avenue, the researchers basically threw up their hands and said that the task was impossible.

The problem is further compounded by the fact that metabolic rates tend to be different for men and women. Age will also play a role. The research suggests that body weight plays an even bigger role in the determination of human metabolic rates.

So, the dissenting researchers appear to have one criticism which is not valid and one criticism that is valid. Therefore, this question has a middle-of-the-road answer. While the 3500-calorie rule is a useful benchmark, it should not be regarded as a hard scientific fact. Think of it as a general guideline rather than a strict rule. In practice, there are a lot of things that can affect your metabolic rate and affect the results. It is probably not fair to call Wishnofsky’s work invalid. He acknowledged that his number was only a ballpark figure, so use it as such.

Pure Fat Vs. Body Fat

It is important to understand the difference between pure fat and body fat. Pure fat is exactly what you would expect: It is made of fat and nothing else. Pure fat is usually white in color, and a good example would be a bucket of lard. Pure fat is not very common in nature, as most creatures do not store their fat in this form.

Body fat is composed of fat cells (technically called adipocytes), but it also contains a large number of other substances. As you probably know, body fat is kind of like the body’s reserve fuel tank. Excess nutrition is stored as fat, and since this fat is derived from food, it’s naturally going to contain things like protein, vitamins, and other nutrients. The body has a need to do this because it cannot live on fat alone.

This factor affects our answer because it throws a wrench in the works of what should be a simple answer. It has been ascertained that a pound of pure fat contains about 4100 calories. A pound of body fat is obviously going to contain less.

How Many Calories Do You Need To Burn In A Day?

So, let’s attempt to determine how this information can benefit you. As we mentioned earlier, the 3500-calorie rule is meant to be a functional rule. The usual method of using this rule is to reduce your daily caloric intake by 500 calories per day. Since 500×7=3500, it is assumed that you can lose a pound per week in this manner.

Here is some interesting research to consider. In this study, researchers attempted to find a mathematical formula that would allow them to predict human metabolic rates with a greater degree of accuracy than Wishnofskys’ rule. Unfortunately, their model doesn’t seem to be completely accurate either.

When we look at the graphs and charts associated with this study, we find that their “dynamic model” still had flaws. It was definitely more exact than the 3500-calorie rule, but outliers and exceptions still kept the equation from being completely reliable.

We can get a little more information from this study. Although these researchers were also unsuccessful in finding an accurate way to predict metabolism, they did find one very useful detail: The fact that all the data changes when the subject gets their total body fat down to 30 kg (about 66 pounds) or less.

Overweight individuals will burn calories at a slightly higher rate than others. In essence, this is the result of the brain telling the body to go ahead and use as much energy as is needed. When the body has an excess of energy, it’s not going to be as careful in spending that energy. Think about it in terms of money. When people have a lot of money, they tend to spend recklessly. When they have less, they tend to spend it more frugally. The body works in much the same way when dealing with its fat reserves.

These researchers found that the 3500-calorie rule was partially correct, thus partially vindicating the old research. In the end, there is only one significant factor that Wishnofsky didn’t take into consideration. That isn’t so bad, because it means that we can still use his rule if we apply a slight modification.

Figuring Out Your Personal Numbers

Let’s start by figuring out your total body fat mass. We will be neglecting the old BMI (body-mass index) method because research has often suggested that a straight percentage is likely to be more accurate.

So, how do you find your body fat percentage? The math is a little bit complex, and the numbers are approximate. Instead of trying to learn all that, just try using this handy calculator that gives you a (more or less) accurate percentage based on your weight, sex, and waist circumference.

How do we use this number to find the total mass of our body fat? This is a simple matter because we have all the information that is required. You know your weight, and now you know your approximate body fat percentage. By putting these two numbers together, the answer is obtained.

For example, let’s assume that you weigh 210 pounds. Let’s also assume that your waist is about 36 inches in circumference (the same as the first number of your pant size). Using our calculator, we can see that your body fat percentage is roughly 18%. Therefore, 18% of 210 is our total body fat mass. Multiply 210×0.18 to get the answer, which is 37.8 pounds. This is well below the 66-pound threshold, so the standard version of Wishkofskys’ rule does not apply to you.

For functional purposes, you could go with a 4100-calorie rule if your body fat percentage is less than 66 pounds. This number is chosen because it is a maximum number, based on the fact that pure fat contains 4100 calories per pound. If you really want to quantify your weight loss in this way, that number should help you to obtain the desired results, even if it isn’t technically correct.

If you would prefer more exact numbers, the National Institute of Health has created an online calculator similar to the one we used earlier. They require only your height, weight, sex, age, and general activity level. This will give you a more exact idea of how many calories you need to burn for an optimal workout.

Controlling Your Calorie Intake

To help you control your caloric intake, you should adopt a low-calorie diet. Obviously, you will still be dealing with some hunger issues. However, these low-calorie foods should give you the energy you need without ruining your weight loss efforts:

  • Oats
  • Greek yogurt
  • Most soups
  • Berries
  • Eggs
  • Popcorn (unbuttered)
  • Chia seeds
  • Fish
  • Cottage cheese
  • Potatoes
  • Lean meat
  • Legumes
  • Most fruits


At the outset, you may have thought that this article was just going to answer a simple question. However, it turns out that this question wasn’t simple at all. Like many fitness-related issues, the main determining factor is the physical qualities and habits of the individual. It is no surprise that scientists have often faced confusion when attempting to determine metabolic rates and/or calorie usage.

Nevertheless, we hope that you can walk away from this article as a more informed person with a better understanding of how human metabolism works, and how you can use it to plan your workouts effectively. If we have succeeded in that goal, you can show your appreciation by following us on Facebook.

The post How Many Calories In A Pound Of Fat? appeared first on Gaspari Nutrition.

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