‘To help us achieve good nutrition, rigorous science is critical and of particular importance now in light of the covid-19 pandemic…’
A study led by researchers at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) has found that people on a low-fat, plant-based diet ate fewer calories but had higher insulin and blood glucose levels when compared with eating a low-carbohydrate, animal based diet. The researchers said that the study was designed to ‘determine whether high-carb or high-fat diets result in greater calorie intake.’
The findings, which have been published in Nature Medicine, compared the effects of the two diets on several indicators including calorie intake, hormone levels, and body weight. The researchers say that the work broadens understanding of how restricting dietary carbohydrates or fats may impact health.
In the ‘small but highly controlled study,’ which was conducted at the National Institutes of Health (NIH), Maryland, US, researchers housed 20 adults, without diabetes, for four continuous weeks in the NIH Clinical Center’s Metabolic Clinical Research Unit. The participants, 11 men and nine women, received either a plant-based, low-fat diet or the animal-based, low carbohydrate diet for two weeks. At the end of this time the diets were immediately swapped. The low-fat diet was high in carbohydrates; the low carbohydrate diet was high in fats. Both diets were minimally processed and had the equivalent amounts of non-starchy vegetables. Participants were given three meals a day plus snacks and could eat as much as they desired.
The main results showed that people on the low-fat diet ate 550 to 700 fewer calories per day than when they ate the low-carbohydrate diet. Participants lost weight on both diets, but only the low-fat diet led to significant loss of body fat.
The study’s lead author Kevin Hall PhD, NIDDK Senior Investigator commented; ‘Interestingly, our findings suggest the benefits of both diets, at least in the short-term. While the low-fat, plant-based diet helps appetite, the animal-based, low-carb diet resulted in lower and steadier insulin and glucose levels. We don’t yet know if these differences would be sustained over the long-term.’
NIDDK Director Griffin P Rodgers MD added; ‘To help us achieve good nutrition, rigorous science is critical and of particular importance now in light of the covid-19 pandemic, as we aim to identify strategies to help us stay healthy. This study brings us closer to answering long-sought questions about how what we eat affects our health.’