No. You can still eat there. When you get there, your appetite will drop, plus altitude sickness. It will become thinner.

You can't lose weight on an empty stomach. This will rebound quickly. First of all, you should pay attention to your diet, and don't eat too much greasy and meaty food. Eat more crude fiber vegetables. Pay attention to the control of food intake, and control it at eight points full. No meals after meals. Drink more water. Eat some raw tomatoes when you are hungry, and you'd better go to the drugstore to buy some lotus leaves, and make tea with lotus seed soup as water to drink. Take a few more roads if you can.

This is my road, two months, from 150 to 122.