Low-calorie diets: It is harmful to reduce your daily calorie intake lower than 1400 calories per day, because your body adjusts to a semi-starvation state and looks for alternative sources of energy. In addition to burning fat, your body will eventually burn muscle tissue. Because your heart is a muscle, prolonged starvation will weaken it and interfere with its normal rhythms. Low-calorie diets don't meet the body's nutrition needs, and without nutrients your body cannot function normally.
Every expert ever will tell you that crash diets don’t work, are unhealthy, and offer at best a temporary fix since you may end up gaining back more than you initially lost once you fall off the wagon. But that doesn’t mean losing weight has to be a slow, torturous process either. Yes, you’ll still have to eat few calories than you burn, but nutrition and exercise researchers have uncovered some scientifically tested ways to make that easier and faster than ever.
REALITY: Fats and carbs both play a role in fat loss. Fats are responsible for hormone production, joint lubrication, and many other important health and muscle-building factors. Dropping your fats too low could compromise your health and your goals. Everyone's body and metabolism is different, so it's crucial to know how many grams of healthy fat you need to eat for a balanced nutrition regimen.
A study from Canada’s McMaster University (partly funded by Dairy Farmers of Canada) put women on several different diets (lower protein, low dairy; lower protein, medium dairy; higher protein, high dairy) and found they all lost the same amount of weight — but that the higher-protein, high-dairy group lost the most belly fat while also gaining and holding onto the most muscle mass. “It seems… increasing calcium and protein in the diet may help to further promote loss of fat from the worst storage area in the body,” said Andrea Josse, lead author of the study.