It's great that you are planning to incorporate some physical activity in your daily routine for maintaining a healthy lifestyle. Eating calorie dense foods thinking that it would lead to weight gain is not correct. You must:-
a) Set your metabolism levels right by following a strict dietary regime and setting your body clock right
b) Include foods that are nutrient as well as calorie dense
Next Steps
Include things like almond and banana shake in your diet, add dates to it. Add roasted sesame seeds to your vegetables. For more action points, you can contact me on direct consult.