There's a growing trend of endurance athletes switching to a low-carb, high-fat diet to avoid the energy crash pretty much every athlete experiences if they don't refuel mid-race. Not to be confused with altitude training (sleep low, train high).
Here’s the gist: Carbs are the most efficient form of fuel for our bodies. They can be digested and converted into energy much faster than other nutrients,
However, our muscles can only store around 2,500 calories of carbs at once, compared to the 50,000 calories of fat. You can teach your body to burn fat as a substrate by restricting your carb intake, which can help you avoid that sudden wall of exhaustion on a long training session caused by a depleted store of carbs.
How it works:
You train on a low-carb, high-fat (LCHF) diet for five to 10 days to teach your body to convert fat into fuel, explains Georgie Fear, R.D., author of Lean Habits For Lifelong Weight Loss.
Your daily diet will come from roughly 50 percent healthy fats, 25 percent carbs, and 25 percent protein. Then, one to three days before a race, you start carb-loading with 80 percent of your diet coming from (healthy!) low glycemic carbohydrates, 10 percent from fat, and 10 from protein. Your body has optimized to burning fat as a fuel, but it also remembers how to process carbs. The theory is that you gain the advantages of training on a low supply of carbs, but you avoid any effect on speed from the missing carbs. You even get an extra energy boost since carbs turn to fuel so quickly
One of the biggest parts of becoming a better, faster athlete, though, is figuring out which training and racing diet is right for you -- and an LCHF diet may or may not be right for you.
While there are huge weight loss and endurance training benefits to this eating plan, it can be a massive undertaking. Test the process and see how it works for you. If, after two weeks of limiting your carbs, you still feel terrible and lethargic on your runs, tweak your plan considering a health professional's advise. Still feel exhausted? A LCHF diet may not be right for your body-and there's nothing wrong with that.