Whole grains such as barley, quinoa, and wild rice are better for you than refined grains like white bread, spaghetti, and saltines in a host of ways. They're loaded with fiber, key vitamins, and minerals; they have been proven to protect your heart and defend against chronic diseases. According to a new study, they may also help with weight loss.
The study from Tufts University found that swapping in whole grains for refined can help you keep a healthy weight and maybe even drop a few pounds.
Researchers recruited 81 adults to test out two separate diets, identical except for grain type, to see how each impacted resting metabolic rate (how efficiently the body burns calories when not moving) and calorie loss (the number of calories burned during digestion). Both of these factors can influence weight loss. After eating the exact same foods for two weeks, the participants followed either a whole-grains diet or a refined-grains plan for the next six weeks.
By the study’s end, the metabolic rate of those fed whole grains had increased while that of the refined-grains group had not. The participants on the whole-grains diet also lost more calories through poop — and those calories weren’t just from the additional fiber itself. The researchers subtracted the fiber calories out of the fecal analyses, so the difference reflected fiber’s beneficial impact on digestion and excretion of other calories in the diet.
The reason whole grains increase resting metabolism and calorie loss is likely tied to two factors, says lead study author Susan B. Roberts, senior scientist at the USDA Nutrition Center at Tufts and founder of the iDiet weight management program. “The fiber in whole grains might increase metabolic rate by smoothing out the metabolic fuel availability in the body,” she explains. “Additionally, the higher-fiber foods may prevent some of the fat in the diet from being absorbed into the bloodstream.”
Although her team didn’t focus on participants’ weight loss or gain — this study lasted just eight weeks after all — Roberts says these physiological impacts can absolutely help you shed pounds over time. “The bottom line of weight loss is calories in versus calories out,” she says. “That doesn’t mean you can eat anything you want as long as you count calories. Rather, you want to choose high-fiber foods that’ll fill you up and increase the number of calories that go out. This can tip the scale in a beneficial way.”
Unlike the complex or highly specialized diets used in many studies, which you couldn’t feasibly follow in real life, this whole-grains diet is very realistic. “We used commercial cereals and breads to add whole grains and fiber and replace more-refined products like white bread,” says Roberts. “It would be totally easy to replicate this diet, and there’s no reason why you wouldn’t get these same benefits. This is a very practical way to help with weight management.”
In fact, you could do even better than this meal plan. For instance, rather than trading in refined white bread for loaves made with whole-grain flour, you can cut back on bread altogether and embrace less-processed whole grains like steel-cut oats, corn, and millet. With the bran, endosperm, and germ still intact and not pulverized, these supply more roughage than their highly processed whole-grain counterparts. And as the researchers note in their paper, having more intact pieces to digest likely means an even greater impact on resting metabolic rate and calorie loss, potentially resulting in weight loss.