This 100%, it took me a while to figure out, as my carbs lower my fats go up, protein usually stays about the same,You need to not just reduce calories, you need to switch macros. More good fats, and saturated is good fat...More protein and less carbs, you should not feel weak after reducing calories to a huge extent if you do it correctly..
Cardio is a must start at a minimum of 20 minutes a day and either increase the duration or add another session in
I personally like incline walking with a weight vest