At 24 you should still have a good metabolism. Mine slowed after 30. When I was in college I lost a ton of weight by doing these things: 1. Never eat fast food. 2. Do eat 3 healthy meals a day. 3. Portion control. 4. Cut out soft drinks. 5. Cut back on alcohol I.e . Make it a weekend treat. 6. Went running on a regular basis. At my peak I was running 5 times a week. Now I only run on an average of 3 times per week, 4 if I'm motivated.