Do diet teas and meal-substitute shakes work to lose weight?

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?


How can I get over my fear of public speaking?

1) I have been a student for two years now and still suffer from terrible anxiety when it comes to doing a presentation or speaking in class. When it comes to presenting in front of my classmates I become so nervous that I can barely speak. I perspire; there is minimal shaking; feel so embarrassed that it even makes me want to cry. Now I even feel physically ill. It has gotten to the point where I refused to do a presentation last semester and my grade was badly affected. I know everyone becomes anxious in such situations but I truly feel there is something else going on with me because I've had to do presentations before coming to school but never felt this terrible. Even speaking in class is a very hard struggle, and my grades depend on it!

2) I have an extreme problem with speaking in front of groups of people (especially speeches). I can't do them! My voice either doesn't say anything, or it shakes like I am going to cry or something. I know public speaking is like the most common fear, but mine is one I must confront. What kind of options do I have besides books? Any ideas?