Great study. I hope someone will add an intermittent fasting to this one, to check. I am not sure if the men's testosterone level raise after fasting is a fact or myth, but if it is true, then this one may help to maintain muscle mass (or even gain when supported with training). It is proven that amount of food one's eat next day after day of fasting is NOT 200% of normal intake. It is about 110 - 120%. And of course human psychology: maintaining caloric restriction is much harder than maintaing every other day fasting or day-to-day intermittent fasting.

Yabbut - it's far easier to just restrict one's eating to a few hour window in the day, and worry less about WHAT you eat, than eating throughout the day and watching EVERYTHING you eat. Fasting isn't "better" it's just subjectively "easier" - and the best diet is the one you stick with.

Calories in, needs to equal or be less than calories spent, will reduce the mass. Even simply lying still, or sitting at a screen.

They need to test 16/8 intermittent fasting as Mike_S stated.
For what it's worth - I started intermittent fasting, 16hr fasting & 8hr feeding - keeping calories the same. In about 6 months I lost about 5 LBS. Doesn't sound like much but I wasn't "over weight" just want to get leaner. I'm 5'6" - went from 156LBS to 150LBS eating the same calories. I continue to do 16/8 but started doing Keto - in 3 months went from 13% to 8% body fat. Keto & 16/8 is a powerful combo at least for me:-) Oh, I'm a 53yo male so there's that:-P

Wonder whether compliance varied across the groups. My expectation is that compliance was better on the fasting group than others.

My doctor wanted me to start checking my blood sugar...pre-diabetic. I've pretty much sworn off sugar, bread, pototo chips and what not.
I also started at the first of the year, delaying eating breakfast until 9am, and lunch until 1:30 PM. By the time I go home I am not hungry
and snack on no/low salt mixed nuts and sugar free lemonade.
I've tightened my belt almost 3 notches and dropped about 15 pounds in the process.

Agree with most of the comments - the different fasting ‘diets’ are much easier to stick with (and you choose whichever variant you prefer). If calorific control was so easy and effective everyone that had ever started a ‘diet’ would have successfully lost weight and kept it off - didn’t happen. With normal diets you’re hungry and missing chocolate every day of your life. Me - 5:2 works well. I’m only hungry for 2 (awake) days a week.

I have lost ~ 12 lbs on a 14/10 intermittent fasting regime,which I started last November. In practice,I usually extend the fasting period by about 2 hours,as I am not hungry in the morning. So if I stop eating at 7pm,I commonly start eating again at 11am. Coffee is allowed, with up to half a cup of milk,as that contains 50 calories,which if not exceeded keeps the body in fasting mode. When I start eating,I eat anything I want,in whatever quantity i want. I tried caloric restriction dieting,but that is a miserable way of reducing weight,as you are always hungry.

These studies can miss the point entirely. I have been doing 16hr for over 15yrs, last yr 18hr as it's gaining momentum as the sweet spot. I am 48 and put on muscle mass like a 25yr old, I gym with abundance of energy, I have high hgh and test, I am 12% b-fat, my bloodwork is impeccable as well. I take no supps other than vitd and some pure grassfed whey protein. I eat clean and whatever and however much I want. Most do not fast for weight issues, they fast for the improvement in all health markers, for autophagy, longevity, for a page full of biological benefits that occur when you enter a fasted state. These benefits do not occur from just 'watching calories', unless you go extreme caloric restriction. In closing, do not be under any illusion these two types of dieting (counting calories and fasting) are biologically remotely close.

I do intermittent fasting and find it effective and easy to stick to.. as others have said I do sometimes start my day with a coffee but thereafter eat nothing until about 2pm. When I tried dieting it simply became too frustrating to measure calories and more often than not I would just end up over-eating. The beauty with intermittent fasting is that the measurement of calories is simple.. until you eat you have consumed 0 calories. That is already inspiring in itself. The secret however is to include some exercise. At this time I am walking about 2.5Km daily and have a set daily step target of 6,500 steps. Having a smart watch helps a lot to keep me on track and I would recommend it to anyone trying to lose weight or stay healthy.