Having done IF while lifting, the issue that stands out to me with this study is that it tested only IF with no advice on exercise or nutrition.

Yes, if you fast without exercise, you will almost certainly lose muscle.

And if you fast without nutritional changes, you likely won't lose much, because IF on its own does not equal a deficit over more than hours at a time.

I gained muscle on IF with ease, and I also lost far more than in their study, with ease.

I'm surprised, given the constraints of the study, that there was an average loss at all.

>Considering Body Builders don’t fast, I tend to believe the study.

There's entire bodybuilding schools (such as LeanGains) that build on intermittent fasting, and its increasingly more common when it comes to cutting fat. Where did you hear this?

> The study only included recommendations to the timing of food intake and did not provide recommendations for calorie and macronutrient intake or physical activity.

> 116 overweight and obese participants

Yeah I mean IF isn't magic. If you sit in front of netflix and eat three 800cal bags of chips it doesn't matter much if you're doing IF or not.

I'm doing IF for years and go to the gym every other day, most of the time fasted. I made good progress, lost fat, gained muscles, and most importantly I feel amazing.

Eating schedule is only a part of the equation. You still need to eat proper food and exercise.

The study run for 3 months and people were under calorie deficit, which is typical time scale when the lean mass starts to shrink.

In general intermittent fast is not a good way to loose fat precisely for this point. In Russia there are fasting resorts where people do not eat for 2-3 weeks under medical supervision. Most people do it not to loose weight but try to improve various medical conditions. Those who go there for weight loss typically gain the weight back since they do not change their eating habits.

As for bodybuilders they do intermittent fasting but not to loose fat but to gain muscles. For some people this works as long as they eat sufficient calories.

Body builders don’t fast therefore fasting reduces lean body mass?