NIH study compares low-fat, herbal diet to low-carb, animal-based diet

Press release

Thursday, January 21, 2021

People on a low-fat, plant-based diet consumed fewer calories daily, but had higher levels of insulin and blood glucose compared to when they ate a low-fat diet. carbohydrates, animal-based, according to a small but highly controlled study at the National Institutes of Health. Led by researchers at the National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK), the study compared the effects of the two diets on calorie intake, hormone levels, body weight and more. The findings, published in Nature medicine, expand your understanding of how restricting carbohydrates or dietary fats can affect your health.

“It is believed that high-fat foods lead to an excessive intake of calories, because they have a lot of calories per bite. Alternatively, foods high in carbohydrates can cause large fluctuations in blood sugar and insulin that can increase hunger and lead to overeating, ”said NIDDK lead researcher Kevin Hall, Ph.D., lead author of the study. “Our study was designed to determine whether high-carbohydrate or high-fat diets lead to higher calorie intake.”

The researchers hosted 20 adults without diabetes for four consecutive weeks in the Metabolic Clinical Research Unit of the NIH Clinical Center. Participants, 11 men and nine women, received either a low-fat plant-based diet or a low-carbohydrate animal diet for two weeks, followed immediately by two weeks in the diet. alternative. The low-fat diet was high in carbohydrates. The low-carb diet was high in fat. Both diets were minimally processed and had equivalent amounts of starch-free vegetables. Participants were given three meals a day, plus snacks, and were able to eat as much as they wanted.

The main results showed that people on a low-fat diet consumed 550 to 700 fewer calories per day than when they ate a low-carbohydrate diet. Despite the large differences in calorie intake, participants did not report differences in hunger, meal pleasure, or fullness between the two diets. Participants lost weight in both diets, but only a low-fat diet led to a significant loss of body fat.

“Despite eating foods high in blood glucose and insulin, people on a low-fat plant-based diet have shown a significant reduction in calorie intake and body fat loss, which provokes the idea that high-carbohydrate diets in themselves cause people to overeat. On the other hand, the low-carbohydrate animal diet did not lead to weight gain, despite being high in fat, ”said Hall.

These findings suggest that the factors that lead to overeating and weight gain are more complex than the amount of carbohydrates or fats in one’s diet. For example, Hall’s lab showed last year that a diet rich in ultra-processed foods led to overeating and weight gain compared to a minimally processed diet, suitable for carbohydrates and fats.

The low-fat herbal diet contained 10.3% fat and 75.2% carbohydrates, while the low-carbohydrate animal diet was 10% carbohydrate and 75.8%. fats. Both diets contained about 14% protein and were suitable for the total calories presented to the subjects, although the low-carbohydrate diet had twice as many calories per gram of food as the low-fat diet. In the low-fat menu, dinner could consist of baked sweet potatoes, chickpeas, broccoli and oranges, while a low-carb dinner could be beef with cauliflower rice. Subjects could eat whatever and how much they chose from the meals they received.

“It’s interesting that our findings suggest benefits for both diets, at least in the short term. While the low-fat, herbal diet helps reduce appetite, the low-carbohydrate animal diet has led to lower and more consistent levels of insulin and glucose. ” said Hall. “We don’t know yet if these differences will be sustained in the long run.”

The researchers note that the study was not designed to make dietary recommendations for weight loss, and the results could have been different if participants were actively trying to lose weight. In addition, all meals were prepared and provided to participants in an inpatient setting, which may make the results difficult to repeat outside the laboratory, where factors such as food costs, food availability, and meal preparation constraints may result in compliance. diets to be difficult. However, the strictly controlled clinical environment ensured the objective measurement of food intake and the accuracy of the data.

“To help us get a healthy diet, rigorous science is essential – and is of particular importance now in light of the COVID-19 pandemic, as we aim to identify strategies to help us stay healthy,” said NIDDK Director Griffin P. Rodgers, MD This study brings us closer to answering the most sought after questions about how what we eat affects our health.

The research was supported by the NIDDK Intramural Research Program. Additional NIH support came from the National Nursing Research Institute under grant 1Z1ANR000035-01.

About the National Institute of Diabetes and Digestive and Renal Diseases (NIDDK): NIDDK, a component of the National Institutes of Health (NIH), conducts and supports research on diabetes and other endocrine and metabolic diseases; digestive diseases, nutrition and obesity; and kidney, urological and hematological diseases. Addressing the full spectrum of drugs and affecting people of all ages and ethnic groups, these diseases include some of the most common, severe and disabling conditions that affect Americans. For more information about NIDDK and its programs, see http://www.niddk.nih.gov.

About the National Institutes of Health (NIH):
NIH, the national medical research agency, includes 27 institutes and centers and is a component of the US Department of Health and Human Services. NIH is the first federal agency to conduct and support basic, clinical, and translational medical research and investigate the causes, treatments, and cures of both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

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