Study focuses on low-carb, high-fat diet effect on older populations

A new study, published in Nutrition and metabolism, of researchers with the University of Alabama at Birmingham’s Nutrition Obesity Research Center observed improvements in body composition, fat distribution, and metabolic health in response to an eight-week, very low-carbohydrate diet.

Older adults with obesity are at high risk for developing cardiometabolic diseases such as Type 2 diabetes and cardiovascular disease. Ordinarily as total fat mass, deposition of fat in certain areas, such as the abdominal cavity and skeletal muscle, can pose this greatest risk for disease development.

The lead author of the study is Amy Goss, Ph.D., RDN, an assistant professor at UAB’s Department of Nutrition Sciences. Goss says her team aimed to determine if a very low-carb, like VLCD, high-fat diet would eliminate these fat deposits and maintain lean mass without intentional caloric restriction in older adults with obesity, thereby improving outcomes related to cardiometabolic disease, such as insulin sensitivity and lipid profile.

“After the eight-week intervention, despite the recommendation to maintain a diet that maintains weight, the group that consumed the very low-carbohydrate diet lost more weight and total fat mass than the control diet group,” Goss said.

Egg consumption was an important part of the VLCD concept. Goss and her team provided eggs to the participants in this diet group and asked them to consume at least three per day.

“Although eggs were part of this study, we can not conclude that our findings are a result of daily egg consumption; but I think what we can conclude is that whole eggs can be included in the diet in a healthier way without negatively affecting blood cholesterol in older adults, “she said.

The primary difference in fat loss between the two groups was from the abdominal cavity and the skeletal muscle deposits.

“We also found significant improvements in the overall lipid profile that would reflect the reduced risk of cardiovascular disease,” Goss said. “Further, improved insulin sensitivity in response to the very low-carbohydrate diet, which reflected reduced risk of type 2 diabetes. In general, we observed improvements in body composition, fat distribution, and metabolic health in response to an eight-week, very low-carbohydrate diet.”

VLCD effect on diabetes

Goss says VLCDs are a therapeutic option for many conditions, including Type 2 diabetes, obesity and non-alcoholic fatty liver disease.

“This study expands previous research to show that it may be a safe, therapeutic option for older adults in their 70s who are experiencing obesity,” she said. “This is the first study to prove depletion of ‘metabolically harmful’ fat deposits, while skeletal muscle is maintained at weight loss in response to a VLCD in older adults.”

Goss adds that there is still some evidence about the benefits of a very low carbohydrate diet in younger populations, and this study was one of the first to test this dietary approach to improve outcomes related to obesity in adults over 65 – a population at high risk for other diseases and in need of therapeutic interventions to improve health while maintaining skeletal muscle mass to prevent or delay functional decline with age.

A good or bad egg?

“Historically, eggs have gotten off to a bad start with the dietary guidelines on egg consumption introduced by the American Heart Association in 1968,” Goss said. “It was recommended that no more than three whole eggs be consumed each week.”

Goss adds that the care stem from the cholesterol and saturated fat content of the eggs. Since then, these recommendations have been disconnected, as more recent research has demonstrated the negligible impact of dietary cholesterol on blood cholesterol. And just this month, the Advisory Committee on Dietary Guidelines published recommendations to increase the consumption of eggs over the entire life span, including pregnant and lactating women, as well as as a first meal for infants and toddlers.

This historic first for the Committee on Dietary Guidelines recognized eggs as an important, nutritious rich food source, because eggs are a rich source of protein, choline, B12, selenium, vitamin D and a long list of other nutrients that are essential for growth and development as well as maintenance of muscle mass, “said Goss.