If you're modifying your diet for optimal training performance, you may find yourself in a seemingly endless debate in the science of nutrition: low-fat or low-carb?
Un recent study, published in the journal Nature Medicine, looked at 20 adults, mean age 30, who were classified as overweight based on their body mass index.
For two weeks, half of the group ate a high-glycemic-load, plant-based, low-fat diet (in which food is quickly digested and absorbed, causing blood sugar to rise more rapidly), while the other half ate an animal diet. This was a low carb diet, ketogenic and with a low glycemic load (in which food is slowly digested and absorbed, causing a slower rise in blood sugar). They then switched diets for two more weeks.
The researchers found that the low-fat diet offered an energy intake less overall, which means I consumed fewer calories. When people were on the low-fat diet, they voluntarily reduced their calorie intake by 550 to 700 calories a day compared to the low-carb weeks. And they didn't comment on differences in hunger, satiety or satisfaction with meals along the way.
This conclusion runs counter to current thinking, the researchers noted, which tends to eliminate low-fat meals because they may offer less satiety, increasing the risk of overeating. Also, eating foods with a high glycemic load can lead to excess insulin production, which promotes the accumulation of fat.
However, in terms of how that affected weight loss, it didn't seem to have much of an impact. Despite considerable differences in calorie intake between diets, weight loss total after the first two weeks it was similar.
What kind of diet is best for athletes?
Like many nutritional questions, the answer is "it depends." Many people, including athletes, believe that if they follow a low-carb or low-fat diet, they will see the desired results. But being low in a certain macronutrient doesn't mean it's necessarily better for you.
Our bodies are designed to need a balance of fats, carbohydrates, and protein, and consuming less energy doesn't always equate to improved performance. For some people, it can even cause them to fatigue sooner.
Athletes need a balance of all macronutrients to perform well. Our bodies prefer carbohydrates as their primary source of fuel and we are very efficient at using them. But we also need fat and protein to help prevent injury, help with recovery, and keep us satiated.
Despite the popularity of low-carbohydrate or fat-limiting eating plans, performance can suffer if athletes intentionally deplete their essential macronutrients.
Instead of focusing on what to reduce or eliminate in a diet, it is better for an athlete to focus on the quality of the food consumed, such as eating complex carbohydrates, lean protein and healthy fats more frequently.