Hi
I'm (coincidentally enough) writing for the diet industry in Aus, but just starting on the project so bear with me. But I can confirm that you can't guarantee a result, but you can offer a permanent solution I believe, unlike the US.
The best place for you to start would be here:
Samples of Weight Loss Ads
Great headlines and advice, esp on the psychology behind weight loss. Also have a look at
www.hardtofindads.com and you'll find many more successful headlines and letters on weight loss.
I agree with previous comments on the first testimonial. Either remove it or make it more obvious that you're introducing Nindini. And, BTW who the hell is Nindini anyway? You have to PROVE to me that this person knows what she's talking about. She could be a world renowned professor in the fields of diets, or some stay at home mother who's selling vitamins to her friends. Build credibility.
The start is a bit clumsy. Why start off telling me what the product is NOT? Try launching straight into it the way you did it after that bit. Just go straight for..."If you're sick of losing weight, only to put it straight back on again, or you want your partner to look at you the way he used to again, or ...... then this is the most important message you'll ever read."
Beef up your guarantee too. Put it in a big box. You could say that she's so confident that you'll lose weight that if you havent lost any weight and feel more energised after only 3 days, she DEMANDS that you get your money back. <insert more proof>... and so she KNOWS it works.
Picky I know, but numbers in 7 are better than 8 (except for the Asian market) so maybe $137 instead of $138.
All in all, it still doesnt read brilliantly. Read it aloud yourself and you'll see what I mean. If you trip up, or try to say something other than what you've written down, then fix it. Imagine that you're saying those exact words to an overweight person directly in front of you. Is that what you'd say?