Would you be willing to give up 300 calories every day? What if we told you that cutting out 300 calories a day could help people improve important health markers as well as lose weight and body fat? 300 calories is a couple of cookies, a small Starbucks Mocha Frappuccino or a large bagel with low-fat cream cheese. Should be easier than you think, right? According to a new study, participants who ate 300 calories less a day lost a significant amount of weight—an average of 16 pounds—by slashing about 12 percent of their 2,500-calorie diets over two years.
Researchers also wanted to examine whether reducing the amount of calories people intake can make an impact on healthy aging and disease. Scientists already know that the strategy called caloric restriction can extend the life span of rodents and other lab animals.
The groundbreaking research was the first major clinical trial to examine the effects of calorie restriction among young or middle-aged adults who are not obese and whose weight is normal or just slightly overweight. The new study looked at a group of 143 healthy men and women who ranged in age from 21 to 50.
The calorie-restricted group had better cardiovascular and metabolic health by the end of the trial, even though their markers were in the normal range when the study began. Participants saw their cholesterol levels improve and their blood pressure fall slightly. They had reduced inflammation and better blood sugar levels.
The lead author of the study, William Kraus, said the extent of improvement in participants’ metabolic health was remarkable. The results go far beyond what would be expected with weight loss, he said. That suggests cutting back on the total amount of food eaten may produce unique biological effects, said the professor of medicine and cardiology at Duke University.
“We weren’t surprised that there were changes. But the magnitude was rather astounding,” Kraus said. “In a disease population, there aren’t five drugs in combination that would cause this aggregate of an improvement.”
Researchers found that the calorie-restricted group reported better sleep, increased energy, and improved mood than the control group of 75 healthy people. The control group did not practice caloric restriction, and members of the control group did not see improvements in any health markers.
The $55 million study called “Calerie,” (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy), was funded entirely by the National Institute of Health. Results were published this July in the Lancet Diabetes & Endocrinology journal.
One scientist who was not involved, Frank Hu, said findings leave questions of whether the study’s changes will mean a longer life span and/or less chronic disease.
While calorie restriction may be a useful tool for dieters seeking better health and weight loss, the Calerie participants’ improvements would have to last over time to guarantee long-term benefits, he said. Hu is the chairman of the nutrition department at the Harvard T.H. Chan School of Public Health.