I really don’t think this could work. (Nice theory though, 
) Because, even if you pigged out in LD’s so you skipped on actual meals because you weren’t hungry, you would gain weight because you would be slowing down your metabolism by not eating. (Still eating regular meals and but eating less and not gorging yourself is an entirely different story. 
) At least, that is my theory. For a while, (I’m just starting to get out of this habit,) I would only eat one meal a day and that was dinner. Not because I’m some sort of , “I must be skinny so I won’t eat anything, kthnxbye,” but because I simply didn’t feel like eating anything. I was never “fat”, but I have lost some weight by eating the normal three meals a day instead of one. It’s really hard because I usually never want to bother with eating so I get my sister to remind me. So…yeah. In conclusion, I don’t think this would work. 
Using lucid dreams to not go on food binges is possible. It was done on a program in the UK a few years ago, where a woman that was clinically Obese was trained to eat food in lucid dreams (and as much as she wanted) so she could enjoy it with out eating in RL and putting on more weight.
It was not used as a fitness method, it was used simply to stop her from binge eating when she wasn’t really hungry.
Yes, it would effectively be known as a starvation diet. The body is a remarkable thing, if you starve yourself it will remember and the next time you start eating it will store more fat that it otherwise would, just in case you do it again.
fitness can be had in a much simpler way if one wishes to cut back on eating so much
solarhealing.com/sungazing.htm
in fact doing this one never has to eat again, ever
for real, i am at 5 minutes and it is fantastically powerful and my vision seems to be improving.
darned clouds though, they’ve been in the way the past 2 days.
I do beleive this could work for certain people. It is unhealthy and not a good idea to use your dreams to make it so you don’t eat, but if you’re the kind of person that will eat more for the taste of the food or something to do than eating because you feel hungry; that is when I beleive this would be great for losing weight. Just eat the food you need, basically and skip food for enjoyment.
Like many have probably stated, no you won’t feel full. However you do feel the pleasures of eating food in your lucid dreams. 
It’s like real life, if you have tasted it before, no doubt you can bring back that same taste in a dream.
I also advise exercising in your dreams, it might motivate you to do it in real life. People use LD for skill learning all the time, at least thats what I hear. I happily plan to implement skill learning/fear facing in my LD as soon as I can induce nightly LD.
I like to refer and think about the entire LD process as “Taking it easy”, I don’t even mind not getting them right now. Everything will happen when it happens, it’s all a flow.
Thanks you very much for nice answer