I lost a lot of weight by eating only dinner every day for a few months.
This is a really good method. For many people, they need to work up to it. Start with eating 3 meals a day, no snacks, 12 hours between end of supper and beginning of next day breakfast. Keep increasing the amount of time with no food. Get down to 2 meals a day in a 6-8 hour window. Then get down to one meal a day. This helps to lose weight and stabilize insulin.
Avoid processed food, especially carbohydrates and "vegetable" oils.
Eat a minimum of 30 grams of protein at every meal.
Walk for one hour every day - all at once or several times that add up to it.
Do some form of weight training (lifting or body weight) two or three times a week.
Fruit is not as healthy as most people think. Fructose, the form of sugar in fruit, leads to fatty liver disease which will worsen insulin/diabetes issues.
This is a good site with information on keto and fasting:
https://www.dietdoctor.com/Some of it is free. Some of it is members only, but you can get a free trial membership.