Summer is here, and due to the heat, many people suffer from loss of appetite, while more and more people enjoy cool beer and late night snacks in the evening when the temperature drops.  This summer is no exception, and no doubt there will be more "Baymaxes" appearing.  For this reason, many people seek simple sit-up methods to solve this problem.  Some coaches and gyms claim that one lesson can quickly lead to  result.  Is that scientific?