As someone who went from 245 to 165 in the course of 1 year, I can tell you without at doubt, weight is lost in the kitchen, not in the gym. The gym is your supplement to the caloric deficit you're seeking to achieve.
If you really want to see an increase in your stamina on-court, on the days you are not doing work in the gym, do the c25k (Couch to 5k) program. A year ago I used to get winded going up and down the stairs. Now I'm relying on my crazy stamina to outlast my opponents in tough 3-setters.
Trust me on this. Do C25K. You can thank me later.
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