Answer :
Final answer:
John maintains his current body weight by achieving energy balance, where his calorie intake matches his daily caloric expenditure, estimated at approximately 2,500 kcal per day for an average adult male.
Explanation:
John is able to maintain his current body weight of 165 pounds because he has achieved what is known in health and nutrition as energy balance. Energy balance is the condition where the number of calories consumed equals the number of calories expended.
For an average adult male, about 2,500 kcal per day are required to maintain metabolism. This means, to maintain his weight, John is likely consuming and using about 2,500 kcal each day. If John were to ingest an excess of 3,500 calories over time without increasing his physical activity, he would gain weight, approximately one pound for every additional 3,500 kcal consumed. Conversely, by reducing his daily calorie intake by 500 calories, or increasing his energy expenditure by the same amount, he might expect to lose about one pound of weight each week.
It's critical to understand that caloric needs can differ based on factors such as age, height, gender, activity level, and even individual metabolism. Therefore, the average figures are general guidelines and may vary for each person. For John, it seems he has found the caloric intake that sustains his weight and ongoing activities.
