If you are a featherweight because you just lost lots -or- because you've always been a bit soft -or- you've just had a baby -or- you yoyo mercilessly -whatever reason, I recommend the book "Thin For Life" by Anne M Fletcher.
You've heard or read the statistic 95% of losers regain their weight? Well, Ms Fletcher spoke to the other 5%. Successful losers, she calls "the Masters".
They talk about food, exercise ... lifestyle ... the maintainers lifestyle. It's an amazing book.
There's actually chapter summaries in the maintainers forum too.
Eat good food. Move yourself. Lift something.