It is common to see marketing for exercise routines that claim to target fat deposits in a particular part of the body. Examples:

But is there any science behind this?

I understand that certain exercises will target certain muscle groups, and can therefore specifically tone your thighs, stomach, legs, biceps, etc, which may make the selected body area look more attractive by some criteria.

But do specific exercises actually burn fat from particular parts of the body more than from others?

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    FYI: Fitness SE has a gazillion questions on the topic, with study-referenced answers, IIRC – user5341 Nov 6 '14 at 13:31

There is no science to back up targeted fat loss, in fact there are studies to refute it.


Two major factors: First,

fat contained in fat cells exists as triglycerides. Muscle cells, however, cannot directly use triglycerides as fuel. It must be broken down to glycerol and free fatty acids, which then enter the bloodstream. As a result, the fat broken down to be used as fuel during prolonged exercise can come from anywhere in your body, not just the part that is being worked the most.


many of the exercises commonly associated with spot reduction do not actually burn many calories.

However, there is some science that supports a very tiny amount of spot-shaping to be possible, but it's very miniscule.


One conclusion:

working a given muscle for 30 minutes at low to moderate intensities did increase fat cell lipolysis in blood flow.


Based on the measured changes in blood flow and lipolysis, the researchers estimate that, in 30 minutes of local exercise, an additional .6-2.1 milligrams (one milligram is one thousandth of a gram) per 100 grams of adipose tissue adjacent to contracting muscle was mobilized.

First let’s assume that you’re carrying a whopping 5 kg (11.1 pounds) of fat in a specific area.

If local exercise can mobilize 0.6-2.1 milligrams of fat per 100 grams of fat mass, that works out to:

0.6-2.1 mg/100 grams * 1000 grams/kg * 5 kg = 30-105 milligrams of fat.
Or 0.03-0.1 gram of extra fat mobilized in 30 minutes of activity.

Now, a single pound of fat (0.454 kg) contains about 400 grams of fat so our hypothetical 11.1 pounds of fat contains 4,440 grams of fat. And 30 minutes of local activity mobilized at most 0.1 gram of fat. Whoo hoo. You’ll be ripped in about 1000 years.

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    Consider talking some about how targeted exercise does effect muscle tone and shape which is often confused with targeted fat loss. – DampeS8N Nov 4 '14 at 18:12
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    Alone the creative conversion from metric to imperial and back to metric units causing 5,000 grams of fat to contain 4,440 grams of fat should perhaps be enough to doubt the conclusions on the web page you're quoting. I can't find the full text of the publication the web site is using as a fact base, but I also assume that the web page author is mixing the numbers for blood flow in ml per 100g tissue per Minute and fat mobilization in mg per 100g tissue per exercise (30 Minutes). – Tor-Einar Jarnbjo Nov 4 '14 at 19:13
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    The math in the last paragraph is sloppy. 0.454kg ≠ 400 grams. 11.1 lb = 5034.9 g (not 4440 g). – Flimzy Nov 4 '14 at 19:35
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    instead of sloppy math, could the difference be to the fact that a pound of fatty tissue contains other things than fat cells or that fat cells aren't entirely lipids? (This would be a different sort of sloppyness.) – Dan Is Fiddling By Firelight Nov 4 '14 at 22:21
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    @DanNeely: It says "A single pound of fat contains about 400 grams of fat." There's not much room for other things in that conversion. I think it's just sloppy conversion. :) – Flimzy Nov 4 '14 at 23:00

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