When cooking and you have leftovers, should they be put in the refrigerator while hot? Or should you cool them first?

I have a weird problem that happened to me once when I was maybe 8 years old (I'm 20 now). I woke up one morning and all dairy products tasted horrible. They tasted as though they had gone bad. I'm not sure how long it lasted back then because I just stopped eating all dairy products for a couple of years — I was afraid they would taste bad, but it definitely lasted several months. When I started to have them again they tasted fine. It seems to have started again. What could possibly be the cause of this?

If you freeze yogurt does it kill the active cultures, the good bacteria?

Despite medication, diet control, and exercise, I still have a ratio problem regarding HDL/LDL. What foods would you suggest to boost HDL, while reducing LDL?

I've been trying to diet for over two years. My goal is to lose about 25 pounds, but the most I've been able to get is 15, and I can hardly keep it off. I concentrate on eating very little and since exercise is so hard to keep up, I pretty much starve myself to death. I manage to maintain the weight for a month, and then I lose control again. I've been thinking about the various diet products in the market, such as diet teas, herbs, meal- substitution shakes, and other medical products. I'd like to know what kind of side-effects they have, and how effective they are. (Some boast a seven-day plan, but that seems hardly believable.) Also, I'd like to know how well-researched the information is on these products (i.e., are they long-term enough to cover all the side-effects?) As for aspartame, is it really harmless, or is it just not researched yet?

1) What's the deal with monosodium glutamate (MSG)? What exactly is it, and how bad is it for you really?

2) I have recently been told I have a strong intolerance to MSG. But I am having trouble in working out what it is in. Is there any chance you could give me a list of items of food in which MSG is present in? I would be extremely grateful for any help.

How much calcium do college-age women need in order to avoid osteoporosis and other such problems in later life? What's the best way to get it? (Calcium, I mean, not osteoporosis.)

Can you explain the difference in healthiness of breads and grains? Are all darker grains better for you than lighter counterparts? Why? If all bread is low in fat, how can it be bad for dieters, etc.?
Thanks!

Do you recommend the natural remedy Ginkgo as a dietary supplement for good health?