For Immediate Release: September 14, 2009
NN: Secrets for a Flat Belly?
Week of October 19, 2009
Contact: Alice Bender, (202) 328-7744
Secrets for a Flat Belly?
Karen Collins, MS, RD, CDN
American Institute for Cancer Research
The secret to a flat belly: Headlines abound claiming that specific foods, nutrients, supplements and exercises somehow selectively melt away the beer bellies and “muffin tops” that spill over our pants.
Waistline fat includes the pinchable fat deposited just under the skin and “visceral fat” that nestles deep around abdominal organs and seems most strongly related to risk of heart disease, diabetes and cancer. Many fat-fighting claims lack research support, but some offer reasonable strategies.
Some studies show that people who eat more whole grains are more likely to have a healthy weight and waistline than those with diets high in refined grains. Studies also link eating patterns that include more refined grains (like white bread) with greater yearly increases in weight and waist. Replacing refined grains and sweets with whole grains could lead to smaller surges in blood sugar and reduced insulin levels. In theory, lower insulin levels could shift metabolic processes to favor fat burning instead of fat storage, but there isn’t research to support the claim.
Whole grains clearly bring health benefits, but simply switching the type of carbohydrate without decreasing calorie consumption may not lead to the loss of belly fat headlines suggest. However, along with reduced calorie consumption, favoring whole grains over refined grains may support a flatter belly. Obese men and women who cut about 500 calories per day lost an average of 10 pounds in a 12-week Penn State study. Those who ate exclusively whole grains lost more than twice the abdominal fat of those assigned to eat only refined grains.
With no change in diet, a Duke University study of overweight adults illustrates the power of exercise. Non-exercisers increased visceral fat by 9% in six months. Those who walked about three hours or jogged two hours a week held abdominal fat levels steady. Jogging about three hours a week decreased both visceral and surface abdominal fat. In this study, participants lost abdominal fat regardless of exercise intensity, so an hour’s walk six days a week might also produce this fat loss, though that was not tested here. In another study participants reduced their daily calories by 400 and did either 30 minutes of vigorous or 60 minutes of moderate activity three times weekly. After five months, people averaged a 26-pound loss, including a 25 to 27 percent drop in visceral fat; use of moderate versus vigorous exercise didn’t affect results.
Studies also support belly-flattening benefits from strength training (such as resistance training with weights or elastic bands). In one study, overweight post-menopausal women decreased their waist size by an average of one inch after four months of resistance training. Other research shows that resistance training can decrease both deep and surface abdominal fat. Spot exercises like sit-ups and crunches are important to tighten abdominal muscles, but they can’t selectively burn up abdominal fat.
Are there extra tricks to help banish belly fat? For most supplements, research is either too limited, shows no effect or actually identifies dangers. Yet catechin phytochemicals (such as EGCG) in green tea may increase fat burning and decrease abdominal fat, at least when added to decreased calorie consumption or increased activity. Studies adding daily EGCG, found in 4 to 12 ounces of brewed green tea, have shown drops of about three-quarters to one inch in waist or about seven percent in abdominal fat in three months, yet results are inconsistent. Products from drink mixes to vitamin supplements may indicate they contain green tea or EGCG yet have only a trace.
Conversely, consuming large amounts of tea can lead to unhealthy amounts of caffeine that may over-stimulate you or interact with medications. We need more research to clarify exactly how much belly-flattening power this strategy can have. Meanwhile, for most people, there’s no harm in adding a cup or two of green tea per day, especially if you use it to replace a high calorie, sugar-sweetened drink.