I gain and lose weight constantly and have been for years. I see a lot of people mentioning counting calories and I've never had success doing that. I stick with Tim Ferris's 4 hour body method of only consuming meat beans and vegetables and getting the 1 cheat day or meal. There are a few other rules like eating 20g of protein right when you wake up, but I can't recommend his book enough to people that are struggling with losing weight. The biggest thing about his book is it makes you understand your body fat percentage and gives you more ways to measure weight loss than just what the scale says, which can be deceiving. Anyways, different things will work for different people, but everything takes time to adjust.

https://www.amazon.com/Hour-Body-Uncommon-Incredible-Superhu...

He also promotes this book:

http://www.amazon.com/4-Hour-Body-Uncommon-Incredible-Superh...

If you look at the reviews you'll get a better understanding.

I suggest checking out the 4-Hour Body by Timothy Ferriss: http://www.amazon.com/The-4-Hour-Body-Incredible-Superhuman/...

The book describes efficient, sustainable ways achieve changes in your body, the premise being to make changes with the smallest amount of work possible. I put on 10 lbs of muscle in 2 months following its weight gain advice. My girlfriend tried the slow-carb diet and saw no effect, but I have heard that working for a few people. It's an interesting read nonetheless and will change your perspective on diet and exercise.

I find that aggregate amazon reviews are fairly accurate. Im surprised by the high reviews. http://www.amazon.com/4-Hour-Body-Uncommon-Incredible-Superh...

Yes, see:

http://www.amazon.com/4-Hour-Body-Uncommon-Incredible-Superh...

I haven't read it yet, but it seems more 'body hacking' than 'fitness,' exactly: http://www.amazon.com/4-Hour-Body-Uncommon-Incredible-Superh...