If you want to lose weight, it’s best to eat more protein and fiber, a new study finds.
Researchers at the University of Illinois Urbana-Champaign developed the Individualized Diet Improvement Program (iDip) and tracked 22 participants who followed the eating plan over 25 months.
Volunteers were advised to increase their daily protein to 80 grams and fiber to 20 grams.
Participants were also encouraged to cap their calories at 1,500 per day, a steep decrease from the typically recommended 2,000-2,500 caloric intake.
41% of iDip participants were deemed successful at the one-year mark, losing an average of 12.9% of their body weight, according to results recently published in the journal Obesity Science & Practice.
The iDip dieters weighed themselves daily and were subject to dietary education sessions, as well as individual advisory meetings.
“The iDip approach allows participants to experiment with various dietary iterations, and the knowledge and skills they develop while losing weight serve as the foundation for sustainable maintenance,” said lead researcher Manabu Nakamura, a U. of I. professor of nutrition.
But around 59% of participants only lost slightly more than 2% of their starting weight after a year.
Researchers believe those who prioritized eating more protein and fiber had the most significant weight loss.
Registered dietitian-nutritionist and first study author Mindy H. Lee maintains that “increasing protein and fiber intake while simultaneously reducing calories is required to optimize the safety and efficacy of weight loss diets.”
The research team did acknowledge the small participant group and the limited observational period in presenting its findings.
The strategy of more fiber and protein and fewer calories is supported by outside research.
Fiber is associated with sustained energy, as it is digested more slowly than other substances. Within the large intestine, fiber triggers the release of hormones that decrease appetite. Because this process takes hours, between-meal cravings are reduced.
While the American Heart Association recommends at least 25 to 30 grams of fiber a day to help regulate bowel movements, control blood sugar and reduce the risk of heart disease and stroke, most Americans are only getting about 15 grams a day.
And while rapid weight loss is typically associated with muscle loss, iDip participants maintained most of their muscle mass.
For those who lost more than 5% of their starting weight, 78% of the weight they lost was fat, researchers said.
They credited the increase in protein intake, as protein aids the body in retaining muscle mass, which then improves metabolic function.
The Recommended Dietary Allowance for protein is 0.8 grams per kilogram of body weight — or 0.36 grams per pound. For a 150-pound person, that’s 54 grams of protein daily.
Nakamura argues that adequate fiber and protein are even more necessary for those using weight-loss drugs like Ozempic that cause a decline in appetite, rapid weight loss and potentially, critical muscle loss.
“The popularity of injectable weight loss medications has been increasing,” Nakamura said. “However, using these medications when food intake is strongly limited will cause serious side effects of muscle and bone loss unless protein intake is increased during weight loss.”
