I was thinking about the advice my doctor gave me that the metabolism resets about every 5 years after age 30. It made me wonder if the recommended calorie intake changes over time as well.

The last time I remember learning about recommended calorie intake was probably in high school health class. Unfortunately, the basic numbers that were drilled into my head at that time (about 2000 calories per day for women and 3000 for men), are correct for teenagers and very young adults but are not good guidelines as you age.

As an experiment, I plugged in the average height and weight data for men and women into the Mayo Clinic’s calorie calculator. I assumed that my hypothetical people were “somewhat active” (i.e. not couch potatoes but not doing regular strenuous exercise either). The only input I changed each time was the age of the person.

Remember, these are the calories necessary to just maintain weight, not to lose any weight.

The results were very interesting. For both men and women, recommended calorie consumption peaks at age 18 and then trends downward. By age 25, calorie consumption should be cut by about 2%, about 5% by age 30, about 8% by age 40 and about 10% by age 50. By age 99, calorie intake drops by almost one-third.

Men start off at age 18 being able to handle a huge amount of calories. Their calorie intake trends down fast, dropping by about 50 calories every 5 years. Women start off with lower calorie intake and drop slightly slower at around 50 calories every 10 years.

50 calories doesn’t sound like much but over time it adds up. For example, by age 40, you should be consuming about 200 calories less than what you ate at age 18—about one good-sized snack.

Of course, you can always exercise more as you age to allow yourself to be able to eat more calories.

Are you surprised at this calorie knowledge? Have you been gradually cutting calories as you age? Please share in the comments.