A 3500 Calorie Deficit Burns a Pound of Fat, Right?

The Science Behind Burning Calories

Nutrition 101 has told us for years burning 3500 calories drops a pound of fat. Recent studies have shed some interesting light on this theory. We're moving into “Nutrition 102” and science will be explaining what's really lost when we burn calories.

Some History

One Pound of Fat
3500 Calories Burns a Pound of What?. MIXA/Getty Images

Let’s start with some history. Max Wishnofsky M.D., conducted the original fat burn research in 1958. He published the 3500 calorie deficit formula which continues to be cited in thousands of educational websites, studies, and scientific articles.

Dr.  Kevin Hall challenged the formula and released a manuscript in 2007. He has redefined the 3500 calories to burn a pound idea. His paper is impressive with enough scientific data and formulas to stump even the brainiest nerd. We will not be jumping into math class right now but sticking with the discovery. 

Following up research published in the International Journal of Obesity is Dr. D.M. Thomas. He has not only debunked the 3500 calories to burn a pound theory, but has also provided three new downloadable applications that “simulates a rigorously validated, dynamic model of weight change.”

Those links are provided at the end of this article.  

3500 Calories to Burn What?

Weight Loss
The Rate of Weight Loss Differs for Each Person. Blend Images/John Fedele Brand X Pictures

Losing fat is a challenge. We have been under the impression simply subtracting 3500 calories per week, we would be able to lose one pound of flab. This is based on the old simplistic theory where 3500 calories represent only fat and not taking into consideration lean mass (muscle). 

New research takes all tissue into account understanding muscle is also lost during the calorie burning process. The amount of muscle lost depends on initial body fat level and caloric deficit.

That means weight and fat loss calculation will differ from person to person. For example, a lean person will tend to lose more muscle and retain fat while an overweight person will lose more body fat and retain lean mass.

This is why an overweight person can better tolerate lower calorie diets and the opposite applies to a lean person. However, restrictive diets are not recommended for either since they're linked to eroding muscle tissue.  

What Does This Mean?

Fat and Muscle
Both Fat and Muscle Tissue are Involved in Weight Loss. Jared DeCinque E+/Getty Images

The original 3500 calories to burn a pound theory needed to take into consideration fat and muscle metabolize (use) energy at different rates. 

A pound of muscle is not 3500 calories but approximately 600 calories. If you applied a 3500 weekly caloric deficit and lost 100% muscle hypothetically that would equate to 6lbs. This would be ludicrous and the takeaway to remember is lean mass loss equals greater weight loss. Losing lean mass is what we're trying to avoid. 

If you created a 3500 caloric deficit and lost 100% body fat then you would lose one pound of fat. Again, this is impossible because both lean and fat tissue are lost during the process. 

Other factors implemented in the new formula applications are caloric deficit adjustments as body weight decreases and energy levels decline. 

In addition, studies recommend stimulating more fat loss to lean mass through progressive resistance training and higher protein intake.  

Can I Still Use the Old Formula?

The 3500 Calorie Formula
The 3500 Calorie Formula Does Provide a Generic Guideline. Peter Dazeley Photographer's Choice/Getty Images

Does this mean throwing the old 3500 calories to burn a pound formula out the window?  No.

Lots of great research went into creating a basic way to figure out daily caloric requirements. Using the 500 to 1000 calorie per day deficit does provide a generic guideline for losing 1 to 2 pounds per week.  

The studies just needed to clarify the inaccuracy of the statement and provide a truer explanation of caloric deficit requirements. Playing around with the new applications will be a fun way to discover what works best for you:

The first link “provides a convenient alternative for providing patients with projected weight loss/gain estimates in response to changes in dietary intake.”


The second link “projects estimated weight loss for multiple subjects and was developed to inform weight change experimental design and analysis.”



International Journal of Obesity (London), What is the Required Energy Deficit per unit Weight Loss?, Kevin D. Hall, 9/11/07

British Journal of Nutrition, Body Fat and Fat-Free Mass Interrelationships, Forbes’s Theory Revisited, Kevin D. Hall, 3/19/07

Annals of the New Your Academy of Sciences, Body fat content influences the body composition response to nutrition and exercise, Forbes GB, 5/00

International Journal of Obesity, Can a weight loss of one pound a week be achieved with a 3500-kcal deficit? Commentary on a commonly accepted rule, D M Thomas et al., 4/30/13

The American Journal of Clinical Nutrition, Caloric Equivalents of Gained or Lost Weight, Max Wishnofsky, M.D., 9/58

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