I just tried that when I was 20. I applied brutal will power and failed miserably, since I lost weight very rapidly and got anemya. Notwithstanding very frequent energization exercises. What I did was to try a raw vegan diet
But now, at 54, I find that I can live with 90% fruit, vegetables and nuts, 2 meals a day, without losing weight.
Sometimes I also feel a bloated stomach, so I might cut more food, and in some days just eat fruit at lunch and salad or veggies at dinner.
Also, a fast on water feels Always beneficial.
One thing for sure, I'm not going to force the body. But now it is far, far easier than it was 34 years ago to live with less gross food.
I'm still doubtful about pure cosmic energy....
I remember that Master (Paramahansa Yogananda) said the food of the future will be sun lite, air and cosmic energy. Eating meat has become tantamount to barbarism and is associated with a by-gone era of migrating hunters.
My dependence on 'heavy' foods has continuously decreased over the decades of being a yogi. i can not even imagine having another human being do the dirty work of decapitating one of my fellow creatures. My sensitivity has increased over years of meditating and also to other beings who have consciousness. The kali yuga is over. Let us evolve as spiritual beings. The vibrations of what we put into these bodies and who we choose as friends can't help but affecting our spiritual vibration. Everything changes for the better as we choose kindness in everything we eat do and say.