When I heard about a study supposedly showing 16 pounds of fat lost and 10 pounds of muscle gained — all at the same time — my BS detector started working overtime.
Either somebody was telling me “porkies” or they had just made an honest mistake.
But when I looked at the research myself, there was no mistake. A group of eight men had lost 16.3 pounds of fat and gained 9.5 pounds of lean mass in just 14 weeks.
Is it really possible to build so much muscle while you’re in a calorie deficit?
The short answer is yes, you can build a significant amount of muscle in a calorie deficit.
However, for the reasons I’m about to explain, not everyone is going to experience such dramatic results.
The results I’m talking about come from a United States Sports Academy study looking at the effects of strength training and aerobic exercise on body composition in a group of overweight (27% body fat) men.
The men were assigned to one of two groups and trained three days per week for 14 weeks.
- An endurance-only group performed both cycling and walking (30 minutes each at 60-70% heart rate reserve for a total of 60 minutes).
- A cross-training group performed both cardiovascular and resistance exercise (8 exercises, 4 sets per exercise, 8-12 repetitions per set, 60 seconds of rest between sets) in a single session. Exercises included the bench press, lat pulldown, military press, barbell curl, triceps extension, leg press, leg curl, and calf raise.
The results are shown in the table below.
As you can see, the group that combined cardiovascular with resistance exercise were able to lose fat (7.41 kilograms or 16.3 pounds) while gaining muscle (4.33 kilograms or 9.5 pounds) at the same time.
That’s pretty impressive.
Truth is, losing 16 pounds of fat and gaining almost 10 pounds of muscle in 14 weeks is a result that most people (and that includes me) would be very happy with.
But as I mentioned earlier, not everyone is going to make such rapid progress.
Firstly, the men taking part in the study were beginners, who tend to make rapid gains in muscle mass when they start training with weights.
They were also overweight (bordering on obese) with a lot of fat to lose.
And if you take someone who is untrained AND extremely overweight (which these men were), they’ll often drop relatively large amounts of fat while gaining muscle at the same time.
People who are very overweight or obese (i.e. your typical contestant on the Biggest Loser) can lose fat a lot more quickly than someone with an average physique who just wants to drop 10 or 15 pounds to look good on the beach.
That’s because your rate of fat loss is heavily influenced by the amount of fat you have available to lose. Or to put it another way, the fatter you are, the faster that fat will come off when you start eating less and exercising more.
But if you’ve been working out for a few years, I don’t want you to go away thinking that these are the sort of results you should be expecting. Because they’re not.
As I’ve explained in this post, losing fat and gaining muscle at the same time is possible.
But unless you’re an overweight beginner, returning to exercise after a layoff, very genetically gifted or using drugs, you’re not going to be able to do both at the same rate.
Losing 16 pounds of fat at the same time as gaining 10 pounds of muscle is just not a realistic goal for most people.
Second, the researchers used underwater weighing to measure changes in body composition.
Although underwater weighing is still considered by many as the “gold standard” when it comes to estimating body composition, there’s still a surprisingly large margin of error, which can skew the results.
As Weightology founder James Krieger points out in his excellent series of articles on the subject, “body fat testing is not a measurement; rather, it is a prediction.”
Researchers have compared underwater weighing with something called the 4-compartment (4C) model for assessing body fat change in individuals.
The 4C model is an expensive method of measuring body composition that divides the body into four components (mineral, water, fat, and protein) and measures each one independently.
Short of killing someone, stripping off their fat and weighing it, the 4C model is currently the best method available to predict body composition.
The results, as James puts it, “aren’t pretty.”
For example, one person showed a 10% loss of body fat using something called the 4-compartment model. But underwater weighing showed a change that was near 0%.
Another person showed a loss of 10% body fat in the 4-compartment model, but a loss of nearly 20% body fat with underwater weighing.
“This means that underwater weighing could tell you that you had very little change in body fat, when you actually had a large change,” adds James.
“On the other hand, underwater weighing could tell you that you lost a huge amount of body fat, when in fact you didn’t lose much.”
Of course, this doesn’t mean that we should ignore the results of this study. But the accuracy of body fat testing is something to keep in mind when you see results that seem a little too good to be true.
Third, the average gain in muscle tells you nothing about the individual results for each subject, which can often vary widely.
Let’s say that you take a group of six men and get them to lift weights for 12 weeks.
Two of the men might make reasonable progress and gain five pounds of muscle. Another two might make slower progress and gain only two pounds.
If we take the results of these four men, the average gain in muscle is 3.5 pounds (5 + 5 + 2 + 2 = 14/4 = 3.5)
But if the other two guys have an easy time putting on muscle (let’s say they gain 12 pounds of muscle), they’re going to skew the results of the group. Adding their results to those of the other four men takes the average muscle gain up from 3.5 to 6.3 pounds (12 + 12 + 5 + 5 + 2 + 2 = 38/6 = 7.3). In other words, two high responders have had a disproportionate influence on the results of the study.
It’s possible that a few of the men in the United States Sports Academy study got outstanding results, which would have boosted the average. The large standard error shown in the results table would suggest as much. But without seeing the individual results for each subject, it’s hard to say for sure.
In summary, some people can and do build muscle while they’re in a calorie deficit.
But it’s a phenomenon that’s generally limited to people who are very overweight and have never lifted weights before, or those who are returning to exercise after a layoff, where muscle memory comes into play.
Once you’ve move past the “overweight beginner” stage, building muscle while losing fat is a goal that becomes progressively harder and will normally require some kind of calorie cycling strategy if you want to see decent results.
SHAMELESS PLUG: If you want a complete step-by-step system that will help you build muscle, burn fat and build the body of a superhero, all while spending less than four hours per week in the gym, click here to download a copy of Muscle Evo right now.
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My name is Christian Finn. I run a private "members only" website that will help you burn fat, build muscle and get strong. If you want accurate, honest and in-depth reviews on the latest "hot topics" in the world of fitness, you're confused by all the conflicting advice out there, or you just want some fat-burning and muscle-building training routines that work, click here now to find out how I can help you.
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