Low-carb diets in general and for endurance sports

As we touched on low-carb diets in another discussion, I thought it would be helpful to make it a separate topic.

Check also this post about how much carbs (and why) you should aim for on easy, moderate, and hard training and competition days. There is no getting around the need to consume carbs for performance in intense workouts and competition.

Like others, I too had a long phase during which I ate no more than 100-120g of carbs/day (circa 2015). I did that for about 2-2.5 years, but it wasn’t sustainable, even though I was following the advice of a Dietician. I lost a ton of weight. It all backfired though when I did not have enough energy for hard efforts and races. I didn’t really know that was the case though, because I was new to intensity training on the bike and racing, so I just thought I was still developing/learning. What made me stop and take a hard look at it all was when I lost my period for 3 months. I thought I was entering menopause at age 42… and I was also constantly irritated and impatient, snapping at the kids for no reason.

With more research and in talking to other nutritionists, I came to find out that such a low-carb diet is only indicated in very specific cases, most of which to manage a health condition. For the healthy, general population, and specially for the active ones, low-carb has negative consequences. Since then I had the opportunity to dig deeper into the subject as part of my Precision Nutrition certification.

One of the reasons low-carb diets are so popular is because it’s somewhat easy to lose weight that way. What a lot of people don’t realize is that all diets work by decreasing the energy we consume (calories), and not by some “magic” interaction of protein and fat that turns the body into a “calorie burning machine” or “increases metabolism”.

These fads like to make it complicated so businesses can sell products and diet plans. But really it is very simple:

  1. We need all macros for optimal health; and
  2. Losing weight follows the law of thermodynamics: if the energy we consume is lower than the energy we spend, we lose weight, regardless of the types of food we eat.

Does that mean we have to count calories? Nope. Counting calories can be off by ~25%! The way to do it is by creating habits that are simple and go back to where we started: getting reacquainted with the feelings of hunger (we have been taught to eat “on the clock” or at social events when everyone else does instead of when we are truly hungry), feeling of fullness (again, many of us was told to “clean our plates” or “take one more bite” and that overrides our fullness signals), portion size and good food choices (fewer processed foods). There are others, but that is the foundation that I will use to coach people in the area of nutrition.

But putting all the science aside, when we think about humans and the way our bodies work, it makes intuitive sense that we need a good balance of everything for the body to function properly. Severely reducing or excluding one macronutrient from our diets will negative impact how our bodies work. Our brains, our cells, our organs, they all use protein, carbs, and fat. Unfortunately the consequences might take years to show up… and at that point we might be deep in the hole.

Lastly, take a look at this article on low-carb diets: https://www.precisionnutrition.com/low-carb-diets


Sharing another helpful resource - guidelines for daily carbohydrate intake:


Sharing an excellent summary of the most current science on the topic of keto and the endurance athlete