I've read a lot lately about midnight snacking and late night eating and obesity and calorie worries, but my problem lies in the opposite direction — I'm LOSING weight, and insatiably hungry, day and night! The only advice I get is, "Eat healthy," which is preaching to the choir, since I consume more fresh produce, mostly vegetables, and home-cook all my own meals. At a recent nutrition check-up, the nutritionist patted me on the back in congratulations for having one of the healthiest lifestyles he's seen, and shrugged at my inexplicable hunger. The fact is, I'm in the kitchen every other hour, and my body doesn't differentiate between awake and asleep anymore when it comes to hunger. I go to bed on a full stomach, and wake up every three hours to eat again. It's exhausting! I'm falling asleep during the day — but never more than an hour, because hunger strikes. And amid all this, my grocery bill climbs and my weight drops. I don't get it. What am I doing wrong?

I just checked serving sizes for different kinds of nuts, and it turns out that I eat 500 to 1,500 calories worth of nuts every day. I eat a couple of different types (almonds, peanuts, cashews) and nut butters. I've never had a problem with this; I'm on the thinner size of average and feel relatively healthy. I know nuts are healthy for you, but can they be too much of a good thing?

A friend of mine and I were disagreeing about this point and I thought maybe you could help. I have heard that it is not possible to both lose fat and build muscle mass simultaneously: ideally, a person should do cardiovascular exercise with dieting to lose extra body fat, and then start to focus on building up muscle mass. He says it's possible to both burn fat and build up muscle over the same period of time. Which is the case?

I get the apples provided in the dining hall on campus every day and have noticed that they are completely coated with wax (scratching the surface produces white flakes). I was wondering, how harmful is the wax if I eat two or three apples a day?

I have a question about walking for weight loss. My walking buddy believes the theory of walking distance is what helps you lose weight best versus my theory that it is the speed at which you walk that matters. So, could you help me figure this one out? Which matters most in ultimate weight loss: speed or distance?

When working out in the gym, machines, such as treadmills and stationary bikes, show how many calories you are burning. Are these calculations correct, or is it just something to keep the participants happy?