Intermittent fasting is popular. However, you should not expect to lose weight unless you also restrict your caloric intake. But there are still many important health benefits to intermittent fasting.
Not eating anything for 16 or 18 hours every day. Or not eating anything for two days a week. These are typical examples of popular intermittent fasting protocols, often followed by people who want to lose weight. The idea is that the body begins to tap into its fat stores when it doesn't receive food during the fasting period, resulting in weight loss over time.
“There are indeed many health benefits to intermittent fasting, but fasting itself does not lead to significant weight loss”, says Philip Ruppert, a postdoc at the Department of Biochemistry and Molecular Biology, where he studies the body's energy metabolism and has a particular interest in ketogenesis; the state where the body burns fat instead of carbohydrates.
Together with Sander Kersten, a professor at Wageningen University and Research in the Netherlands, he has authored a review article summarizing and discussing existing research on metabolic processes such as ketogenesis and fatty acid oxidation that come into play during fasting. The article is published in Trends in Endocrinology and Metabolism and can be seen here.
As someone who eats once a day for convenience and not as a diet this misses the point of those diets. At the end of the day, the only thing that matters when losing weight is calories in and calories out. No human has ever beaten thermodynamics, and if you have then congrats on your Nobel prize
That being said, putting strict limits on your eating does two things. First, it's actually tricky to consume 2000+ calories in one sitting. Obviously people do it, and I've done it plenty of times, but most people would be miserable to regularly consume that much food in one sitting
Much more importantly in my opinion is that it forces you to pay attention to what you eat. I think a lot of people (Americans especially) consume a lot of "invisible" calories. A few chips here, a sip of soda there, a piece of candy between meetings, a red bull before shift, etc. I think many people have several hundred calories a day they consume and don't even realize that it's going into their bodies. When you make all of your consumption specific and regulated it makes those extras stand out more. I think the most successful "diets" force the person on them to mentally acknowledge everything that enters their mouth. That consciousness makes slipping in an accidental 150 calories in junk that does nothing for you harder
Cutting 1 soda per day at ~150 calories per soda is 1 lbs lost every 3 weeks. You won't feel any different without that soda after a week. In comparison burning those calories would mean around 30 minutes of walking per day. That's a lot of time regardless of how you feel. The saying goes "you can't outrun a bad diet" and intermittent fasting really succeeds at making you conscious of your consumption