Need help !

Weigh your food and log everything accurately and honestly. That's all there is to it.

If you're stuck studying a lot, every hour on the hour make sure to get up and stretch a lot. Maybe do some jumping jacks and or other light calisthenics. This helps keep your body out of slug mode. It would be most beneficial if you could do this more frequently but 1 hour at a time could give you a good amount of time to study too without the constant interruptions. Take stairs whenever viable and park at the farthest spots in the parking lot. It's a lot of little things that add up quickly.

Calculate how many calories you burn on a daily basis, there is a lot of online calculators that will help you do this. Take this number and subtract 500 from it and that is how many calories you need to allow yourself to eat daily. For example if you burn 2000 calories everyday, you eat 1500 calories. If you create a caloric deficit of 500 calories everyday, you will burn 3500 a week, which equates to a pound. So every week you will be losing a pound or more. Calculate the calories on everything you eat. You can still drink diet soda as long as it has no calories. I wouldn't recommend this to everyone but you could skip breakfast which would give you more than enough calories for the rest of the day and you don't even have to work out. Eat lots of protein or you will lose muscle when losing weight. Protein also makes you feel more full.

Eat at a caloric deficit and you'll lose. This means weigh and measure everything you consume.