A proper methodology would be to have all 3 groups consume the same 7-day baseline diet for 2 weeks, then switch into the IF groups and monitor increases in rate-of-change for body weight vs net body weight difference before/after. There should also be similar caloric input for all groups before and after program to see if there is actually an additional benefit to intermittent fasting vs caloric input reduction.
I think that the logic of giving even less to those fasting is pretty obvious that it would lead to more weight loss.
You can read the full study here, but it seems to confirm a caloric defecit on the IF2 and IF group vs control.
https://nutritionj.biomedcentral.com/track/pdf/10.1186/s1293...
...
IF1-P, 9058±692 kcals/week vs.
IF2-P, 8389±438 kcals/week
A proper methodology would be to have all 3 groups consume the same 7-day baseline diet for 2 weeks, then switch into the IF groups and monitor increases in rate-of-change for body weight vs net body weight difference before/after. There should also be similar caloric input for all groups before and after program to see if there is actually an additional benefit to intermittent fasting vs caloric input reduction.