There's more evidence that occasional fasting — actually, just eating very lightly — can help people lose weight.
People who ate a special low-calorie diet five days a month not only lost weight, but lowered their cholesterol, blood pressure and body fat measurements, researchers reported Wednesday.
On average, dieters lost around five pounds after three months on the diet.
They also experienced less evidence of inflammation, which is linked with cancer, heart disease and obesity. They appeared to have better control of blood sugar, which is a risk factor for diabetes.
This particular diet is called the fasting-mimicking diet and it’s based on a specific product line that provides 750-1,100 calories a day from food bars, soup packets and teas.
“Three fasting-mimicking diet cycles reduced body weight, trunk and total body fat; lowered blood pressure; and decreased insulin-like growth factor 1 (IGF-1). No serious adverse effects were reported,” Victor Longo and colleagues at USC’s Longevity Institute, School of Gerontology and Department of Biological Sciences wrote in their report, published in the journal Science Translational Medicine.
Longo founded the company that developed the diet products, but said he doesn’t profit from them. The study was funded by the National Institute of Aging and the National Cancer Institute. He said the products provide a careful balance of plant-based nutrients that are heavy on unsaturated fats and complex carbohydrates.
“These are really dramatic effects,” Longo said in a telephone interview.
The team started with 100 volunteers, most of them overweight but not obese. The researchers said 70 of them stuck with it for the full six month study.
Half lived and ate normally for three weeks each month, and then followed the diet for five straight days. Half did nothing different. After three months, the non-dieters went on the diet.
“We chose five days because it was the minimum needed to get the effects,” Longo said.
“It’s possible that if you went longer, you would have additional effects," he said, noting that people would not stick to such a low-calorie diet for so long.
“It’s a compromise between efficacy and compliance,” Longo said.
Longo and his team have been studying this approach for years in animals. They’ve extended the lives of lab mice with similar intermittent fasting diets. They can’t show that sort of thing in people, especially not over such a short time.
But Longo said his team will use the results to ask for permission from the Food and Drug Administration to do a bigger study, with the goal of proving that the diet can lower the risk of diabetes and perhaps help people control the disease better.
Longo thinks the diet affects many different processes, from cholesterol production to blood-sugar control, and even the production of immune system cells.
Not only do people stop eating meat, dairy and processed foods for the five days, but the foods in the diet products provide a planned balance of fiber, amino acids, vitamins and other nutrients, he said.
How important is the prepared product? Longo thinks it’s difficult to combine all the factors in the diet without having a ready-made product. It’s also very difficult to get FDA approval for something intangible like guidelines. And, he said, people might mess up if they try a do-it-yourself approach.
Here are the ingredients of one of the soups in Longo’s product, which is called ProLon: rice flour, dried onion, inulin (chicory fiber), dried tomato, dried carrot, salt, dried red pepper, dried leek, potato starch, olive oil, freeze dried basil, spinach powder, dried parsley and natural flavor.
A 270-calorie food bar contains: almond meal, macadamia nut butter, honey, pecan, coconut, flaxseed meal, coconut oil, vanilla and sea salt.
Americans badly need diet approaches that actually work. Overall, 38 percent of U.S. adults are obese and 17 percent of teenagers are. Another third or so of Americans are overweight. Forty percent of adult women are obese. If approved by the FDA, a bigger study could change the way Americans think about diet and weight loss.