The promise of all "miracle" diets. But is it really a good thing?

Every time you lose weight, you lose a combination of fat and muscle. The more restrictive the diet and the less strength training you do, the more muscle you'll lose. This leaves you worse off than at the beginning, because with less muscle, even if you're thinner, you have less caloric expenditure due to muscle loss.

What's the solution to this problem?

1) A calorie deficit of up to 500 kcal. Losing 1% of your weight per week is considered a healthy goal.

2) Prioritize strength training (calisthenics and/or weight training)

3) Maintain a good protein intake. It's preferable to reduce carbohydrates and fat, since protein prevents muscle loss and helps maintain it if you strength train.

For steps 1 and 3, any calorie-counting app will work (you don't need to weigh your food and obsess about it; any improvement in your current state will help you over time). For step 2, if you can't or don't want to go to the gym, any YouTube workout routine for muscle gain can help.

Remember, the most important thing is to make your daily routine sustainable.