Vitamin B12: Like folate, vitamin B12 is needed for producing and maintaining new cells. It is also needed to maintain the sheaths that surround and protect nerve fibers. An inadequate amount of B12 causes pernicious anemia. Signs of vitamin B12 deficiency are fatigue, weakness, constipation, loss of appetite, weight loss, and numbness and tingling in the hands and feet. An excess intake of folate can mask the symptoms of B12 deficiency, so it's important to have your levels checked by a blood test, especially if you consume a vegetarian diet. Vitamin B12 is found in animal products like trout, salmon, beef, and dairy foods. There are fortified cereals that provide B12 as well. Doctors do not routinely check vitamin B12 levels.
A systematic review in 2018 looked at 16 studies on the ketogenic diet in adults. It concluded that the treatment was becoming more popular for that group of patients, that the efficacy in adults was similar to children, the side effects relatively mild. However, many patients gave up with the diet, for various reasons, and the quality of evidence inferior to studies on children. Health issues include high levels of low-density lipoprotein, high total cholesterol, and weight loss.
If you eat fewer calories than you burn, you'll lose weight. But when you're hungry all the time, eating fewer calories can be a challenge. "Studies show people who eat 4-5 meals or snacks per day are better able to control their appetite and weight," says obesity researcher Rebecca Reeves, DrPH, RD. She recommends dividing your daily calories into smaller meals or snacks and enjoying most of them earlier in the day -- dinner should be the last time you eat.