When i see people start workouts, exercise or healthy eating, I always see everyone just get rid of all prior foods and go straight to this healthy stuff.
With how the body functions you should slowly come off one thing and go on to the next.
Also Cheat meals are good, i'm not the healthiest eater, i have my junk food, but i eat a lot of my meats and veg,
bearing in mind i'm suppose to be having around 3200 calories a day xD
Situps are not the best, they can actually cause damage to the muscle and ligaments over time, For core/abs workout best thing for them, is to do other things, such as Planks, Russian Twists, or bent legg raises, WITH your lower back flat on the floor, and not arched, otherwise your back will start to get damaged.
Also Crunches are classed as the one of the worse exercises for fat burn or calorie burn due to it not activating much in the way of muscle fibers xD.
Also please say your doing these 50 situps and 100 pushups in sets of like 12-15 reps or anywhere between 12-20 reps per set with a break of between 30-60 seconds for adequate/efficient workout.
FINAL THING:
DO NOT go straight in to a workout, ALWAYS work your way up, with situps i can easily do them, with around 20kgs on my chest no problem, but when i have a break from them, i will always start with 1 set of 20-30 max no weight, and slowly add.
AND WARM UPS + STRETCHES!!!!!
Diet plans and workout routines from websites and a lot of trainers are good and all, but most diet plans are designed for 1 type of person, with everyone being different everyone requires different foods, amounts of calories, and other factors, most diet plans don't count for this.
Also with workout plans, they are always set the same with everyone, they do not personalize them to each person.
My sugestion is to get your learn on, do research on exercises etc and make your own routine that fits you.
Ohh 1 final thing, if your trying to gain weight then you want to be intaking 200-400 calories extra a day maybe 600 at most.
if trying to lose weight, then you want to be eating 200-400 calories under your normal calorie intake a day.
If you want to speak more, message me on steam or come on TS