It’s time we had this conversation.
LCHF and fasting for female athletes are being criticized of late, and I feel we’ve lost perspective. We need to be really mindful of our definitions and always understand the exact dietary prescription being studied or commented on. On a more general note, one example that immediately comes to mind is the study by Burke et al. titled, A Short-Term Ketogenic Diet Impairs Markers of Bone Health in Response to Exercise, which attempted to show that a long-term keto diet could deplete bone mineral density and bone strength. Importantly, the carbohydrates prescribed were 0.5 g/kg/d which would be 30 grams of carbohydrates/day for a 60kg female and 40g of carbohydrates/day for a 80kg male (for example). In no way do I ever recommend carbohydrates this low, not even for the type II diabetics I work with! Secondly, nutrition studies almost never account for food quality. So while the study energy matched the high carbohydrate group to the low carbohydrate group (meaning that equal calories where consumed between groups), some of the foods consumed by the low carbohydrate group include peanut butter cookies, choc pecan cake, “low-CHO bread”, whipped cream, créme fraiche and Eden cheese. Check out the sample menu in this study. This is again not how I and many others define LCHF, which is predominately plant based, moderate in protein, mostly omega-3 fatty acids and little to no dairy.
When it comes to LCHF and fasting for females, please consider:
1. It’s not unhealthy or dangerous to eat more plants, high quality protein and healthy fats. These are the most nutrient dense options there are.
2. It’s not unhealthy or dangerous to swap refined carbohydrates for whole food carbohydrates. I hope this is obvious.
3. It’s not unhealthy or dangerous to check in with the volume of fruit or starch you eat, in fact if you don’t, you often end up under-eating greens, protein and healthy fats.
4. It’s not unhealthy or dangerous to simply eat breakfast when you are hungry, rather than the minute you wake up. Everybody fasts. We’re not talking about water or dry fasts here.
5. It’s not unhealthy or dangerous to exercise at a light to moderate intensity before breakfast. I almost always recommend an MCT Coffee prior, which provides ~250 calories and still counts as fasted training for the purpose of this discussion. We do need more research on fasted training in female athletes and an important definition will be between those who are fat adapted and those who are not. We simply can’t study a sugar burning metabolism and extrapolate the results to every female athlete.
6. LCHF is not keto. For female athletes, 75, 100 or 150g of carbohydrates per day from wholefoods is not unhealthy or dangerous. You may need more in the luteal phase of your menstrual cycle, but you still don’t need 400-600g/day, I promise.
So before you freak out at a news headline or new study that’s released, take a deep dive and truly understand whether what is being discussed is a reflection of what you eat or have been prescribed to eat.
And like everything in life, it’s relative. So if you are of menstrual cycle age, use your cycle as your monthly report card. And considering seeking personalised support if you are not getting an A+ each month.
Want to learn more? Check out my episode on the Triathlon Taren Podcast, Low Carb Training For Women here.