you dont eat for a week and you would lose alot of weight and yes people say its unhealthy but atleast you loose wait and people say you will put weight back on put what if you just ate fruit and veg? could it work .
Initially, you would lose water, then your body would go into starvation mode and hold onto the fat. You would also start to slow down, as the body would try to conserve energy, so you'd feel very lethargic. Eventually, your muscles would be used as fuel and whilst you may look skinny, you would look untoned and emaciated.
Just go to the gym and eat healthily and in moderation.
also during your week of no food you have to fight your food cravings which may lead you to binge. you may not think its a worry now but after a few days of no food your resolve may not hold up.