"The ketogenic diet, which is an extremely low-carb but high-fat diet, is a really restrictive diet," says Rachel Lustgarten, RD, of the Comprehensive Weight Control Center at Weill Cornell Medicine in New York City. As weight drops, so do estrogen levels, says Luiza Petre, MD, a board-certified cardiologist and nutrition expert based in New York City. To find a dietitian in your area, search the Academy's Find a Nutrition Expert database. Here, you will find awesome keto…