High-carb and High-fat Diets Compared
Plant-based diets high in carbohydrates and meat-centred diets high in fats have become increasingly popular in recent years, and a new small, tightly controlled study has investigated their effects.
A myriad of health benefits ascribed to plant-based diets, while high-fat, low-carb diets have been proposed as a way to counteract overweight and diabetes risk. But there has been little understanding on how exactly the two diets compare, given that they restrict either fats or carbohydrates.
The answers to these questions were sought by a team at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).”High-fat foods have been thought to result in excess calorie intake because they have many calories per bite. Alternatively, high-carb foods can cause large swings in blood glucose and insulin that may increase hunger and lead to overeating,” said the study’s lead author, NIDDK Senior Investigator Kevin Hall, PhD. “Our study was designed to determine whether high-carb or high-fat diets result in greater calorie intake.”
The study took 11 male and 9 female non-diabetic participants and housed them in a facility for four weeks. For two weeks, they were served either a low-fat, high-carb, plant-based diet or a low-carb, high-fat meat-based diet. They were then changed to the other diet for the next two weeks. The food was minimally processed, contained equivalent amounts of non-starchy vegetables and participants were allowed snacks and to eat as much as they wanted.
The participants ate 550 to 700 fewer calories per day than when they ate the low-carb diet. Despite this difference, participants reported no hunger, and the same level of fullness and satisfaction with both diets. The participants lost weight on both diets, but more so on the low-fat diet.
“Despite eating food with an abundance of high glycemic carbohydrates that resulted in pronounced swings in blood glucose and insulin, people eating the plant-based, low-fat diet showed a significant reduction in calorie intake and loss of body fat, which challenges the idea that high-carb diets per se lead people to overeat. On the other hand, the animal-based, low-carb diet did not result in weight gain despite being high in fat,” Hall said.
The results add to a growing body of evidence that shows that diet is much more complex than just total calories. Hall’s previous research found that participants who ate highly processed food let to overeating and weight gain compared to a minimally processed carbs and fat-matched diet.
In this case, however, there were benefits observed in both diets.
“Interestingly, our findings suggest benefits to both diets, at least in the short-term. While the low-fat, plant-based diet helps curb appetite, the animal-based, low-carb diet resulted in lower and more steady insulin and glucose levels,” Hall commented. “We don’t yet know if these differences would be sustained over the long term.”
However, weight loss was not a goal of the study, and that may have influenced participants’ eating behaviours and the outcome of the study. The inpatient setting of the study also controlled what foods were available, unlike daily life where a variety of options, costs, preparation and availability concerns influence food choices.
Source: Medical Xpress
