Like the keto diet, the plan is heavy on proteins—but it's light on pretty much everything else. According to its website, it's "one of the fastest and most efficient diet!" (That typo is the Thanon diet's—not ours—and it's one of many on the plan's website.) Another immediate warning sign: The diet isn't officially endorsed by the hospital where it was developed. But that's not where the red flags end.
So...What Is The Thonon Diet?
Every day for a full two weeks, you're supposed to limit yourself to 600-800 calories per day. There's no exact protein intake you should aim for, but there is an oddly specific meal plan: You're supposed to consume a cup of unsweetened coffee or tea for breakfast (sometimes a splash of milk is allowed—or a modest side, like a small piece of whole-grain bread!). Lunch is always built around protein: It might be one or two hardboiled eggs with an unsalted vegetable or poached fish with tomatoes. For dinner, you're supposed to eat something like steak or ham with optional vegetable garnishes. Cheat dinners (within reason) are allowed on the seventh and 14th days, but alcohol is always off-limits.
Then comes the "stabilisation phase," in which women are supposed to 1,200 calories per day (it lasts for an unspecified amount of time). In the morning, it's unsweetened coffee or tea again, with either a small amount of yoghurt or a glass of milk; a small piece of bread with a bit of margarine; and either fruit or a glass of fruit juice. Lunch is vegetables with 100 to 150 grams of protein—in the form of meat, fish, or fried eggs—with unsweetened cottage cheese and fruit. Dinner is a bowl of homemade soup with vegetables, a small potato, a small portion of protein, greens with a little bit of margarine, a slice of bread, and a fruit. Between-meal snacks consist of yoghurt or cottage cheese.
If that sounds like a lot of sacrifice, well, that's because it is.
Okay, But...Does The Thonon Diet work?
Theoretically, yes, although the strange and monotonous meal plan would probably be hard for most people to stick with, says Samantha Rigoli, a registered dietician with Healthy to the Core in New York City. You might lose weight initially, but keeping it off would be another story entirely. And in the short term, people who eat primarily protein with only trace amounts of fibre might find themselves constipated and uncomfortable.
This article originally appeared on Women’s Health US.