John exercises for one hour four times a week but it's done to learn he is not losing weight or fat in order for him to lose weight is important that he

Explanation:

When a person wants to lose weight, he should change his whole life style which includes Healthy eating, physical activities, proper exercise and avoiding junk foods. A person who wants to lose weight and burn fats from the body, he needs to make a deficit of 200 to 400 calories per day in order to lose weight in a healthy manner.

So if john is not losing weight despite of his exercise routine, the reason is definitely that he is not eating healthy or he is eating above his daily calorie barrier. It is a fact that a exercise only contributes 30 to 40 percent towards losing weight, whereas eating below your calorie barrier would contribute the rest of the 60 to 70 percent towards the weight loss.

In order to lose weight, John should limit his daily calorie intake.