Lose Your Gut

New Study: Crunches Don’t Burn Ab Fat

Lose Your Gut - New Study: Crunches Don’t Burn Ab Fat
By Daniel Gwartney, M.D.

Everyone grab your infomercial ab products! A new study has finally answered the question as to whether sit-ups, crunches and those quirky hold-a-dumbbell-and-bend-to-the-side-back-and-forth exercises shed belly fat.

Now, toss that junk in the trash can if it claims to drop inches off your waist in bold colors directly below the spandex-clad beach bunny or GQ underwear model.

Let’s be clear— exercise is a vital component to developing musculature, including the various muscles that form the “core.” Exercise is also a major factor involved in reducing body fat and it is very effective when combined with a maintenance or hypocaloric diet.

The average person not only is seeking to lose fat for the overall health benefit; he or she is typically fixated on one “problem area.” Many women are concerned about the appearance of “fleshy arms” or the eternal nemesis— cellulite. Yet, for men and women alike, the primary culprit is the belly. Late at night, or throughout the weekend, informercials hawk all varieties of exercise programs and widgets that promise a midsection like actor Daniel Craig’s (of James Bond fame). The implication is that working the abs will not only provide a rigid washboard of muscle, but also melt the overlying fat away in a tsunami of spot reduction.

So, the question nearly everyone wants to know is, “Can I get a six-pack in six minutes, or even 60?” Even scientists wondered, given the ubiquity of the claim. Thus, there have been several studies published. The general consensus is that unless the exercise volume meets the ACSM (American College of Sports Medicine) recommendations of 150 minutes weekly and is coupled with a hypocaloric diet, there will not be any overall fat loss.1 But there have been some conflicting reports. A study published in 1965 demonstrated a statistically significant decrease in the waistline following four weeks of abdominal exercise training without weight loss.2 This would probably impress the men and women in the math club more than the dancers in the night club. However, it is supported by a study that compared subcutaneous fat of a trained arm versus the untrained arm after 12 weeks in subjects. In that study, the trained arm had less subcutaneous fat as measured by skinfold technique.3 The change in skinfold is not considered the “gold standard” way to measure fat loss. Finally, a reduction in the fat cell size was noted in subcutaneous fat overlying muscles exercised using isometric techniques.4