Would increasing my calorie Intake cause quick weight gain?

Iunas wrote: »

I’ve been eating around 600-800 calories a day and my meals included very high protein so I stay full. I just want to know that if I should go from 600-800 to 1,500 cals for a whole week and I need to know if that would cause fast weight gain.

Sure, it might cause a temporary gain on the scale, but that wouldn't be fat gain, as you are a male and the minimum you should be eating for weight loss is 1500 calories anyway.

Are you WANTING a fast weight gain or trying to PREVENT one? If that last, you can bump your calories up 200-300 per week.

As a male, the very minimum you should be eating is 1500 calories which is aggressive and also assumes you're sedentary. I'm a middle aged male who works a desk job and I lose about 1 Lb per week on 2300-2500 calories per day. I do exercise daily, but it's nothing crazy. Hell, my breakfast I'm eating right now is 600 calories.

Any weight gain will be attributable to increased water weight and more inherent waste in your system. 1500 calories per day is significantly lower than maintenance calories for pretty much any male, so you aren't going to get fat.