Bork
Based on the information you gave me (5'11'' and 175 lbs), you have a BMI of between 24 and 25. In other words, you are in the 'normal' range. Losing extra weight is not needed. Just a good balanced diet and regular exercise.
I have a BMI of 28, which makes me overweight, but less than obese. As long as I keep fit, and eat a good balanced diet, also no problem.
According to the BMI chart I looked up, a "normal" weight for my height ranges between 140lbs and 180lbs. I'm pretty sure the definition of "normal" is slanted to accomodate the excessive eating and sedentary lifestyles so common these days. For example, Britney Spears might still be classified as "normal" in the west, but she was looking pretty jiggly last time I saw her on TV. I'm targetting 160lbs for now, I'm very confident I'll be there within a few months, but what really matters to me is whether I can see my abs properly. If you don't have 6-pack abs however big or small, it means you've got excess fat on your stomach and it's not at all unhealthy to try trimming that down.
As most of us know by now, your muscles don't get their energy directly from the fat surrounding them, so if you want to trim fat around your belly or somewhere else, the only effective way to do it is to slim down on the whole. Crunches and situps will make your abs stronger but they still won't be toned, because they'll still have layers of fat surrounding them. Carefully controlling stress levels and nutrition can help make your body store less fat in the stomach and more fat elsewhere, but it's much easier and faster for most people to just get their body fat indices down on the whole.
Have you ever seen the amount that skinny people eat?
It's pitiful.
I knew a woman at work, who was very thin.
She claimed she ate like a horse, but her lunch was two small sandwiches.
A fat person would have snuffled them up as a starter.
I've read that there are people out there whose bodies lack the enzymes to digest certain starches and such, so i.e. there are a minority of people out there who can eat copious amounts of certain breads and never gain an ounce. Still, I'd personally prefer being able to get nutritional value out of anything I eat, and use mental discipline to control my health in situations where there's too much food on the table.
But yeah, once I started watching the "lucky" skinny people around me, I realized I had been too much of a porker in my younger days. I stopped drinking a litre of Coke every day and switched to the diet stuff, that made a huge difference all on its own (yes I know diet isn't considered the best choice either, although most of the things people say about it come out of the wrong orifice). Even the ones who claimed to eat like a pig, there were plenty of times they would have their meal and I'd think it was just an appetizer, also there were plenty of times when they wouldn't eat anything at all because they were too busy boozing or whatever.
If you can live with a bunch of skinny people, do what they do, eat nothing they don't eat, and exercise as they exercise, and you still haven't started to look skinny like them, then there's probably either a serious medical issue going on, or you're not being diligent enough about duplicating their example.
What size meals and what frequency is an interesting question. There are various schools of thought, but little good scientific data.
I doubt there's any evidence indicating that your metabolism will skyrocket if you eat 5 small meals a day. I couldn't see the effect burning more than a few hundred extra calories at most- if your body just ups and burns an extra 1000 calories a day without running around and lifting weights, you're going to feel unbelievably overheated, because that's pretty much where all the extra energy would go. I think the primary logic behind eating many small meals a day is that it helps to control and reduce your appetite. Just like they say take your time with eating, your body takes a while to inform the brain that it's had enough.