Exercise

February 19, 2011

Spot Reduction Silliness

I must get at least a half-dozen emails a day asking some sort of variation of the following question: “What exercise can I do to reduce the fat in my (fill in the blank with a problem area).” No matter how the question is phrased, my answer is always the same: sorry, but there is no such exercise…

I’ve said it over and over in my books and magazine articles and I’ll say it again here: you can’t spot reduce fat. It’s a physiologic impossibility. All the sit-ups in the world won’t give you a flat stomach; no amount of leg raises will preferentially slim down your saddle bags. In reality, trying to zap away your problem areas is literally an exercise in futility.

Here’s why spot reduction doesn’t work. When calories are consumed in abundance, your body converts the excess nutrients into fat-based compounds called triglycerides, which are then stored in cells called adipocytes (a.k.a. fat cells). Adipocytes are pliable storehouses that either shrink or expand to accommodate fatty deposits. They are present in virtually every part of the body including your face, neck, and soles of your feet.

When you exercise, triglycerides in adipocytes are broken back down into fatty acids, which are then transported via the blood to be used in target tissues for energy (note: fat cells and muscle have separate blood supplies). Because fatty acids must travel through the circulatory system—a time-consuming event—it is just as efficient for your body to utilize fat from one area as it is another. (Side note: muscles do contain their own internal fat stores called intramuscular triglycerides that can be used directly by the muscle for fuel, but these stores have no impact on your appearance.) Bottom line: the proximity of adipocytes to the working muscles is completely irrelevant from an energy standpoint. Simple, right? Well, perhaps not…

Several years ago, a research group from Copenhagen, Demark came out with a study that seemingly challenged common wisdom about spot reduction (1). In short, the study showed that fat breakdown was greater in fat depots adjacent to working muscles compared to distant muscles. This led the researchers to conclude that “specific exercises can induce ‘spot lipolysis’ in adipose tissue.”

Say what? After that extended physiology lesson, does this actually mean that spot reduction is a reality? In a word: No! Lipolysis (i.e. breakdown) does not necessarily equate to oxidation (i.e. fat burning). As noted, the fatty acids mobilized from adipocytes adjacent to working muscles aren’t just morphed into the muscle for use as fuel. They would still have to travel through the circulatory system to reach their intended destination, which may or may not occur. If not, the fatty acids would simply be repackaged into triglycerides and stored back in adipocytes. Bottom line: the study did not in any way show spot reduction; it simply showed a very slight increase in mobilization from the underlying muscle, which means next to nothing in the overall scheme of losing body fat.

Mark Young, a very astute fitness pro, did an excellent job analyzing the shortcomings of this study in his blog post, Spot Reduction is Real?. Check it out and you’ll see how research can be misconstrued if you simply look at the overall findings of a study and don’t delve into the particulars.

Stay Fit!

Brad

1) Stallknecht B, et al. Are blood flow and lipolysis in subcutaneous adipose tissue influenced by contractions in adjacent muscles in humans? American Journal of Physiology. Endocrinology and Metabolism. 2007 Feb;292(2):E394-9.