I am very interested in nutrition and enjoy eating a well-balanced diet because it makes me feel healthier, happier and more energized. I also have a terrible sweet tooth, which I combat by simply not buying junk food when I shop for groceries (although I will indulge on rare occasions). This strategy has worked for me very well — up until now.

I am living with my boyfriend who, despite even his doctor's warnings, has a rather unhealthy diet. In an effort to nudge him in a better direction, I have offered to cook most of our meals at home myself, but with little success. He's a picky eater and often declines the meals I prepare in favor of pizza or Chinese take-out instead. I would just give up and let him clog his arteries, but his unhealthy habits are starting to affect me. When he brings home tacos, or especially bags of candy, I inevitably eat them also. I am a decent cook, but a greasy pizza always tastes better. If I can't change his habits, how do I at least keep him from changing mine?

I've just been told that I lack iron in my blood. So, I'm curious, what is the worst thing that could happen if I don't do anything about it?

I am writing in hopes that your answer to this question will help other readers. A few years ago, when I was in college, I discovered that my college roommate was bulimic. My boyfriend and I found evidence in the mornings that she had been vomiting on a daily basis; she also developed weird eating habits (at 6 A.M., she would wake up and buy two pints of ice cream and eat it all, and then not eat for the rest of the day). We didn't know how to address the problem, and were afraid of hurting her. When we called the Health Service, they took the "my best friend is bulimic" line to suggest that I was bulimic instead! I didn't want to become the food "hall monitor" — are you eating? What did you eat today? etc. — but we tried to include her in healthy meals.

Eventually, some other stress factors in her life calmed down and her binge/purge behavior seemed to subside. However, I've always regretted that I couldn't attack this situation head-on. Do you have any advice for people that might be in a similar situation?

A friend of mine bought me a month's worth of yoga classes over the summer. I loved it! I've never found an exercise/fitness regimen that I actually WANTED to stick with. It helped with a lot of my long-standing physical issues (balance, back pain, stress, fatigue) and was a perfect balance of stretching and strengthening for my fitness goals. The only problem is that now that my month is over... I can't really afford to do it anymore. I've looked all around for inexpensive and conveniently located studios, but I can't find anything that's in my price range or fits in my schedule. What resources are there for broke aspiring yogis? Are there any guidelines for practicing yoga at home? Are there any exercise routines that are similar to yoga (i.e., low impact, stretching + strengthening) that are less expensive or easier to do without an instructor?

Here's a food preparation question: I made a large tomato sauce with meatballs and several pork chops in it. I cooked it for two hours and turned the heat off at 1:00 AM and went to bed without putting it in the refrigerator. I awoke at 8:00 AM and the sauce was a few degrees above room temperature. If I reheat the sauce, will it be all right to eat? Thanks.

I know there are video games out there now that require you to move more, unlike traditional video games. Are these games, like Wii Fit, a good way to be more active or are they doing more harm than good?

A coworker of mine was drinking a green liquid at the office and told me that it was "chlorophyll water". Neither of us are sure what the health benefits of ingesting chlorophyll are, and it's hard to find reliable info on the internet. Is this fad based in medical fact, or is it just a weird new drink to try?

My question is about nutritional supplements, specifically androstenedione and its closely related cousins. I have a five-day-a-week workout routine, and I have been searching for a supplement that will give me the greatest benefit for all of that hard work. I am, however, very concerned about the negative effects of some of these unregulated supplements. My question then is, what kind of side effects can I truly expect from using one of the male hormone precursors like androstenedione? And, in your opinion, is it safe?

For as long as I can remember, I've been using my back muscles when I did sit-ups. In fact, I distinctly remember the first time we did them in second grade. After a few reps, it was already so painful that I was having trouble breathing properly. Being eight years old, however, I didn't realize this was a warning sign and assumed it was normal.

Flash forward ten years, and I have almost no strength in my abdominal muscles. I've tried to teach myself to do curl-ups properly, but no matter how hard I try, I can't even lift my head without using my back muscles. Exercise balls are no help either. Even when I concentrate on using my abs to keep myself steady, my back is still doing 95% of the work.

So, in short, I have two questions: Am I at risk for having damaged my back from years of abuse, and how can I work on strength training my abs now?

Almost every place that I go to, I see stores and stores just devoted to selling vitamins and more vitamins, and I was wondering what the benefits are of a normal healthy person taking vitamins daily. Are there any risks for a normal healthy person who doesn't take vitamins? Will the person taking vitamins' health be improved or have longer longevity? Will the person not taking any vitamins be as healthy as the person who is taking them? And also, what will happen if a person takes more than he or she should consume every day?

A friend of mine takes laxatives to keep her weight under control. The directions on the box say that you should only take two a day for no more than a week. She has been taking two to six a day for two months now. I was wondering what possible physical side effects might result from this kind of activity.

1) Which foods, if any, have negative calories?

2) I have recently started a weight loss plan and after doing some research I learned about calorie burning foods. My question is, are there really calorie burning foods or is it just another diet fad?