Since LeBron James tweeted a picture of his slimmed-down 6-foot-8 frame, his weight loss has sparked as much interest in low-carb diets as the Atkins’ craze did back in 2004. The news from ESPN writer Brian Windhorst on Twitter and the jokes from LeBron himself on Instagram have everyone speculating why he’s doing it and what it means for his performance on the court.
The basic, scientific concept behind James’ weight loss and low-carb diet is simple: train the body to rely on fat for fuel. The goal of restricting your daily intake of carbohydrates is to create a metabolic state called ketosis, where the body uses fat as a source of energy instead of glucose (aka carbs) in the blood and liver. When carbs are restricted low enough, the body will produce ketones, which can be used as energy—something that Dr. Jeff Volek says is inherently in our genetic code.
“There is a growing number of athletes who have been told that they need carbs and now you see them questioning that conventional wisdom,” says Volek, co-author of two books including, The Art and Science of Low Carbohydrate Performance. “It does take at least four weeks to adapt to the diet but almost anyone can do it and it’s something they can maintain through competition.”
As James’ recent photos indicate, some of the immediate effects of the diet change are weight loss and better overall body composition. But Volek, who is also a professor at Ohio State University, says a low-carb diet has other, less visible advantages for elite athletes as well. “There are benefits related to recovery and even cognition and mental clarity—the brain is very efficient at using ketones as a stable fuel source.”
Los Angeles Lakers nutritionist Dr. Cate Shanahan also uses James’ low-carb lifestyle approach with her team, but she puts a different spin on it.
“The term 'low-carb diet' should really be substituted with the term 'low sugar diet,'” says Shanahan, who helped Dwight Howard reduce his carbohydrate intake and cut out candy bars. “In order for carbs to absorb into the blood stream, they turn into glucose—whole grain or not it’s going to go in as sugar.”
Getting the athletes off of their high-sugar, “Fruit Loops and soda” diets is just part of her PRO-Nutrition program, which focuses heavily on eating good fats. According to both Shanahan and Volek, the key to a successful low-carb plan is getting exactly the right amount of protein (too much will limit the production of ketones) and the right types of fat (monounsaturated and saturated fats are preferred; too much fats from soy or safflower oils can be problematic). If protein is over-consumed, Shanahan says, it makes it tough for the kidneys to process the excess nitrogen and get it out of the body safely.
Because fat and protein needs are so different for everyone and so important to an effective low-carb diet, Shanahan says it’s crucial for her to closely monitor the athletes to make sure they are improving their fat burn. Blood tests, ketone and blood glucose strips, urine tests and a metabolism measurement tool called a metabolic cart help Shanahan assess a player’s progress and make it easier to make small changes to the diet.
For Indiana Pacers’ nutritionist and registered dietician Lindsay Langford, the low-carb approach is just a trendy diet. While she does agree that a ketosis state and restricted carbs can help with weight loss, Langford worries about some of the potential risks.
“The diet is typically really high in saturated fats which can cause isolated lipid levels, and blood pressure and cholesterol issues,” says Langford, who has worked with the Pacers since October 2013. “You really do have to watch the players to avoid the dangers of low blood sugars and make sure they are achieving the appropriate caloric range.”
Despite the possible dangers, Shanahan says that if James is successful with his low-carb approach, he “will be a monster” on the court next season. After watching athletes in the NBA, she says players’ energy fluctuations between the first and second halves are obvious, “performance plummets because the sugar burners are so pumped up on adrenaline, which drops drastically after halftime.” The best thing an athlete can do is to go through the metabolic shift induced by a low-carb diet.
“Everything that an athlete wants they can get by becoming an expert fat burner,” Shanahan says. “If he can do that, he won’t rely on adrenaline and the muscles will work much more efficiently.”
For now, we’ll have to wait until October to see if cutting carbs will help LeBron James be a fat-burning, championship-earning machine in Cleveland.
Fattier versions of beef, chicken, turkey and fish
Eggs, cream, cheese and butter
Nuts and seeds
Olive oil and coconut oil
Fruits like blueberries, raspberries, tomatoes and olives