I currently do 1500-2500 pushups in a given week and the same in sit ups but i feel very slugish and i know its cause of my bad eating habits whats the best way to stop buying sodas etc.. and eat healthy i find this so hard to stop existing habits
It takes alot of willpower at the start. You just have to do it and replace the unhealthy snacks with fruit or some almonds for example. Replace the soda with water or if you want some flavor get some crystal light packets that you just add to water. It will be tough at the start but your body will thank you and you'll be able to tell the difference in your energy levels.
You obviously know at least one reasoning for your "sluggishness", however I think the bigger question is why are you doing 1500-2500 pushups and sit ups?