Math & Science: How Weightlifting Burns Fat

It is widely known that a pound of fat has 3,500 calories and that to lose a pound of fat you have to burn 3,500 more calories than you eat.

But how many calories are in a pound of muscle?

Even more interesting, how many calories does it take to build a pound of muscle? What is the added metabolic effect of building muscle? Is fat burned while building muscle?

Nita Marquez, an IFBB professional fitness athelete and coauthor of the Book Fit For Combat, calls weight lifting the triple threat of fat loss. The effort of lifting weights burns calories, more calories are burned to rebuild and increase the muscle tissue and the increased muscle burns even more calories.

The triple threat that weight training provides is often overlooked when people think about losing fat, but peer reviewed research shows that weight lifting is a potent fat burning tool.

In an experiment conducted at the University of Limburg in the Netherlands and published in the Journal of Applied Physiology, researchers found that weight training subjects increased their average daily metabolic rate by 9.5%.

The researchers found the caloric expenditure from the exercise of weight training itself, “could only explain 40% of the increase in ADMR (average daily metabolic rate).”

They concluded, “that weight training, although of modest energy cost compared with endurance training, induces a significant increase in ADMR.”

What then was the 60% increase in AMDR that could not be explained? The calories used to build muscle mass.

In the University of Limburg study, the weight lifting students gained 4.62 pounds of muscle (on average) while losing 4.4 pounds of fat.

Which is why the researchers said in the final line of the report, “[weight training] can be applied as an effective and safe adjunct to exercise based weight-control programs.”

The triple threat to fat posed by weight training is pretty obvious when one looks at the numbers.


Camille Paglia wrote, “Modern bodybuilding is ritual, religion, sport, art, and science, awash in Western chemistry and mathematics. Defying nature, it surpasses it.”

Paglia was dead on in the mathematics part. (If numbers hurt your brain, just skim the next few paragraphs.)

A pound of muscle equals 454grams. That means a pound of muscle is 454grams of protein. A gram of protein has about 4calories.

A pound of muslce then has about 1,816 calories in it.

The weight training students in the experiment gained, on average, 4.6 pounds. On paper, they would need an additional 8,353 calories to build that muscle, but the experiment found that it took more than twice that many calories to build the muscle.

The Average Daily Metabolic Rate of the weight lifters increased from 12.4MegaJoules a day to 13.5MegaJoules a day (it was a Dutch study, hence the MegaJoules.)

The increase of 1.1MJ is equal to 262 calories.

The exercising students were studied for 18 weeks, which means their increased AMDR was equal to 33,012 calories over the course of the experiment.

Forty percent of that AMDR increase could be attributed to exercise, which leaves 19,808 calories over 18 weeks that went to muscle growth.

But, as noted above the 4.6 pounds of muscle would be only 8,353 calories, leaving 11,455 calories unaccounted for during the 18 weeks, or 91 calories a day.

What were those calories doing? They were building muscle, but not necessarily the 4.6 pounds of muscle gained.


When a person lifts weights and trains to maximum failure, it causes micro-trauma to the muscles. Micro-trauma is the little itty bitty tears and pulls that can cause muscle soreness the day after exercise.

If a person is eating enough calories, eating enough protein and getting enough rest, their body will repair the micro-trauma and then add a little bit more muscle.

This process is called musle hypertrophy. A properly designed resistance training program will inflict an amount of micro-trauma on the muscles that the body can fully recover from and add to before the next bout of training.

When a person is in their hypertrophy zone, they are continuously increasing muscle tone, size and strength.

As the researchers at the University of Limburg found, it can have a profound effect on Average Daily Metabolic Rate.

The effect works something like this:

Presume you have “M” amount of muscle. When you work that muscle to maximum failure, the micro-trauma reduces it to “M-1″. During the next few days calories are used to repair the micro-trauma, building the muscle back to the starting point of “M” and then building a little more so that you wind up at “M+1″.

The next week, starting at “M+1″ you inflict enough micro-trauma to bring you back down to “M”. Your muscles repair, building you back to “M+1″ then adding a little more muscle “M+2″.

The 60% increase in ADMR, 157 calories, that could not be explained by exercise is from the process of repairing micro-trauma and building new muscle. Looking at the raw numbers, the repair of micro-trauma alone accounts for 57% of the calories (89 a day) with 43% (67 a day) going to new muscle growth.

The increased muscle (M+1, M+2) also burns a few extra calories every day, completing the triple threat of fat loss which was 4.4 pounds (15,400 calories) for the exercising students.

The math makes it all seem pretty simple. Lift weights to maximum failure and watch the fat melt away. If that were the case, every guy in the weight room would like a cover model for a fitness magazine and obviously that is not the case. It is not the case because somewhere along the line the body adapts.


The most potent aspect of the triple threat to fat posed by weight training is not in the exercise itself or the resultant increased muscle tone or size.

The real metabolic effect is in rebuilding muscle and building new muscle:

M, M-1, M, M+1, M, M+1, M+2

It takes calories to rebuild the muscle “M” after weight training and increase muscle tone and size “M+1″.

If a person is not inflicting very much micro-trauma, or any micro-truama the metabolic effect is minimal or non-existent.

For example:

M, M-.01, M, M+.01

A person could be under-training because they are just not lifting very hard, not lifting to maximum failure or because their body has adapted to the amount of exercise.

Once the muscle has rebuilt itself and grown, it takes an increased exercise load to inflict micro-trauma.

If the muscles fully adapt to the exercise load there is no “M-1″ or even “M-.01″.

At the opposite end of the spectrum would be severe over-training:

Presume again you have “M” amount of muscle. You engage in some insane workouts creating massive micro-trauma “M-3″. Your body goes into the rebuilding process but only gets to “M-1″ before you do another insane workout. You are now at “M-4″.

Yes, the metabolic effect is there, but only for a period of time because the frightening thing about over-training is that the body will adapt to even insane workouts. A person doing the exact same insane workout week-in-weekout can wind up at: M-.01, M, M+.01

It is possible a person could increase the insanity of their workouts, but that would just set the cycle in motion again.

After reading this section the beginner, novice or any sane person would be justified in throwing their hands up in frustration. (Nita and I both experienced bouts of frustration from over-training and under-training. And we hanven’t even mentioned the role of protein intake.)

There is of course a very simple solution to the conundrum: The Rosenfield Rule.


In the University of Limberg study the excising students only worked out just twice a week doing, “three sets of 15 repetitions…on the following exercises: bench press, flies, squat, leg curl, leg extension, seated rowing, lat pull down, dumbbell curl, triceps push down, and sit ups.”

A twice a week total-body-workout hits right in the middle of the hypertrophy zone and is a long way from anything truely insane.

The hypertrophy zone is an amount of work that results in the optimal M, M-1, M, M+1 cycle of micro-trauma, rebuilding and muscle growth.

The authors of the article don’t dwell on finer points of the weight training program but do mention each session was supervised by a trainer. The presence of a trainer and the resulting increase in muscle reported in the article are sure signs the students were following the Rosenfield Rule.

The Rosenfield Rule is simple: Do more this week than you did last week, do more next week than you did this week.

The experiment protocals called for the students to perform three sets of 15 repetitions on each exercise but did not prescribe the weight to be used. If they increased the weight as they became stronger from the increased muscle, they would be following the Rosenfield Rule. They would be consistently doing “more.”

A moderate weight training program of a few basic exercises following the Rosenfield Rule prevents excessive over-training or under-training.

The real fat burning effect of weight training comes from the rebuilding of muscle tissue and building a little more muscle before the next time that muscle is worked.

A weight lifting program that causes too much micro-trauma will deliver results for a period of time but as muscle is lost the effect declines. Training programs that don’t have enough micro-trauma or do not follow the Rosenfield Rule also have declining results which is why not every guy in the weight room looks like a cover model for a fitness magazine.

To maximize the simple math muscle’s metabolic effects a person needs a workout plan that falls near their hypertrophy zone.

A pound of muscle has 1,816 calories. As shown by the University of Limberg experiment, it takes twice as many calories to build a pound of muscle which is why the metabolic fat loss effect of weight training goes far beyond the calories burned in the gym.

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