Control the quantity of food you eat

Eat only when you are hungry.
This will discipline you to eat just the right quantity that your system needs to function optimally.

Aim to eat all your meals before 7:30pm.
At night, insulin is maximally stimulated by food, meaning the same amount of food results in higher insulin levels. This higher insulin level will naturally result in weight gain.

Eat your largest meal in the midday, preferably between noon and 3 pm.
This gives enough time for your food to be digested before bedtime.