In terms of weight loss, how fast is too fast?

IMO, in your situation 1 to 1 1/2 pounds a week at the very most. The slower you take it off the better chance you have of keeping it off. All to often a "Crash" diet, what ever that means, will be followed by some real binge eating and the Yo Yo effect has started. Just go very slow but steadily and you will like the results better and won't feel nearly as bad.

I'm a 160 pound 5' 9" man who weighed over 220 20 years ago. I took nearly two years to drop those 50 pounds but I have kept them off except for one spell when I was sick and lost another 15, the rebound from that took me to 169 before I was able to control it. Just go easy and you will like the results.

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2 lbs weight loss per week is about the max, if you exceed that you're losing muscle as well. So 2 and 1/2 months = 10 weeks , 10 weeks * 2 lbs = 20 lbs. So the question becomes whether that 20 lbs is good fat loss or bad weight loss being you lost muscle and fat rather than mostly fat.

If you are extremely obese then the 2 lbs per week doesn't apply. But based on your description do not go over 2 lbs loss /wk

1-2 pounds per week is healthy weight loss. 20 pounds in 10 weeks = 2 pounds per week. That's a healthy level. I've even heard that up to 2.5 pounds per week may be reasonable. Don't go any faster than that, though. Losing one pound is equivalent to depriving yourself of 3500 calories, and depriving yourself of 7,000 calories/week is about the maximum you should strive for. More than that and you are starving yourself, which isn't healthy for you. It puts you at risk of burning muscle mass instead of fat. Not to mention making you grumpy from not eating enough!

Losing water weight is a day-by-day or hour-by-hour fluctuation. Weight loss over 10 weeks has nothing to do with water. Your body tightly regulates how much water you retain. "Water weight" refers to what is in your digestive tract and urinary system. If you are drinking water when you're thirst, and urinating regularly (once a day at the very least), your body regulates the rest.

Your BMI is perfectly healthy, though. No need to lose more weight! If you do, don't go any faster than 1-2 pound per week, and don't let your BMI drop below 18.

If you are at 6", 160 is fine. You don't need to loose weight. Just work out and tone up what you have. I have given you a link to a height and weight chart below.

save time and money during the week by buying lean protein such as chicken breasts in bulk and cooking a weeks worth on sunday night

90 minute ride on horse back

watch one less hour of tv