Nuts have been linked to all sorts of health benefits, and for good reason. Their fiber, unsaturated fats, vitamins, minerals and other compounds help promote heart health in many ways, notably by improving cholesterol levels, reducing inflammation and helping arteries stay flexible. Observational studies have linked nut consumption to a lower risk of not only heart disease, but also hypertension and type 2 diabetes, as well as lower mortality rates.
The problem with nuts, of course, is their calories—160 to 200 per ounce. We’ve reported in this space on research indicating that these calorie counts may be overestimated by as much as 25 percent, since some of the fat, carbs and protein in nuts pass through the intestines undigested. But even at, say, 130 calories per ounce, nuts are still heavyweights. This scares many people away from nuts, though it shouldn’t.
The researchers behind the headline-making Spanish study on the Mediterranean diet specifically addressed this inordinate fear of weight gain from nut calories. Nuts featured prominently in one of the diets tested, and apparently contributed substantially to its cardiovascular benefits. In the appendix to the study, the researchers wrote that they made a special effort to allay the participants’ concerns about nuts by providing them with a “comprehensive exposition of recent scientific evidence suggesting that these foods do not promote weight gain” and may even help promote weight loss.
Now, some of those same Spanish researchers have taken a further step in exonerating nut calories. In an analysis in the American Journal of Clinical Nutrition, they combined data from 31 clinical trials looking at the effect of nuts on weight. The studies used a variety of nuts, usually one to three ounces a day, for anywhere from two weeks to more than a year.
The result: Diets enriched with nuts did not increase body weight, body mass index or waist circumference compared with control diets. And in studies that required participants to limit overall calorie intake, the nut groups tended to lose more weight than the control groups.
How could nuts help with weight control? Their protein fat and fiber help make you feel full longer, so you’re likely to eat less subsequently.
That’s all good news for nut lovers. But it’s still best to eat nuts in place of other high-calorie foods, especially those rich in refined carbs, and to choose unsalted ones.