As a wannabe weightlifter, training on low/no carbs is a nightmare: no force, no speed, no explosion of powahz! for Olympic lifting.
This is exactly what I found.
For people who just diet and don't do exercise, low carb is fine. In Hollywood, low carb diets are all the rage and they definitely work.
However, when I tried it, simply running for longer than 10 minutes became a serious challenge. I then removed the limitation on carbs, took the day off the next day and "carbed up" and the following day, running for 1 hour was a breeze.
Perhaps other people respond differently, but for athletic performance, I have to be carbed up.
The high fat, low carb diet just doesnt work for me.
Furthermore, those who are practising IF AND doing lots of exercise - I find this extremely difficult to do. Basically, after serious physical exertion, I get seriously hungry. This is the time where your body is able to soak up protein and carbs, the best. So, restricting calorie intake at this crucial time seems (logically) counter-productive.
Another point is that professional athletes do not practise low carb diets or IF diets. They eat nice a clean when they want. They train hard. They are fantastically fit/strong. Why can't we take their lead?