In practice, however, I would be concerned with eating enough. Based on my experience, teaching yourself to consistently eat more is one of the harder parts of intermittent fasting. You might be able to feast for a meal, but learning to do so every day of the week takes a little bit of planning, a lot of cooking, and consistent eating. The end result is that most people who try intermittent fasting end up losing some weight because the size of their meals remains similar even though a few meals are being cut out each week.
A 2018 review of intermittent fasting in obese people showed that reducing calorie intake one to six days per week over at least 12 weeks was effective for reducing body weight on an average of 7 kilograms (15 lb); the results were not different from a simple calorie restricted diet, and the clinical trials reviewed were run mostly on middle-aged women from the US and the UK, limiting interpretation of the results. Intermittent fasting has not been studied in children, the elderly, or underweight people, and could be harmful in these populations.
Before the Nobel Prize was awarded to Yoshinori Ohsumi, other researchers were making groundbreaking discoveries about autophagy. In 2009, an article was published in Cell Metabolism entitled Autophagy Is Required to Maintain Muscle Mass. In this article, researchers described how deactivating an important autophagy gene resulted in a profound loss in muscle mass and strength.
Harvard-trained physician and author of The Paleovedic Diet, Dr. Akil Palanisamy further explains to POPSUGAR that "autophagy is the self-cleaning process by which the body's cells break down and recycle damaged proteins and components. This is activated by intermittent fasting, but anything other than water (even black coffee) disrupts it to some extent."
Yes, by cutting out an entire meal each day, you are consuming fewer calories per week – even if your two meals per day are slightly bigger than before. Overall, you’re still consuming fewer calories per day. This is highlighted in a recent JAMA study[b] in which both calorie restricted dieters and intermittent fasters lost similar amounts of weight over a year period.