How many calories should the diet of a 28-year-old male weighing 200 pounds contain?

Assuming you are about 5 foot 7 (since you want to drop from 170 which isn't much for a 6 foot person) your body burns about 1785.6 calories by its self. You want to shoot for about a 500 calorie deficit to lose weight. Which means if you did NOTHING all day you would have to eat 1285 calories but that is not healthy at all. I would suggest eating about 2000 calories a day in 6 smaller meals spread throughout the day. This now means you have to burn about 1215 calories to get the 500 deficit you want to shoot for to lose weight. Walking around throughout the day will burn some of those off so lets say you have 800 left to burn.

Now you do not NEED a 500 calorie deficit to lose weight but the reason I say shoot for it is because in one week you will lose 1 lbs of FAT, which is a rather large chunk if you've ever seen 1 lb of fat. There are 3500 calories in a pound of fat so 7x500=3500.

If you have an extra two hours in your day which I understand a lot of people dont. Weightlifting for 1 hour will burn about 265 calories unless your going really intense and biking will burn about 673 calories an hour going 12-14 mph giving you 973 calories burned.

Good luck in your venture to weight loss!