You’re eating the same calories per day as you always did, but the pounds keep piling on. And you wonder…
Estimated reading time: 10 minutes
If you eat the same calories per day as you did in your early 20s, and are now past 40, therein lies the problem.
A very fundamental problem—even if you kept your activity levels the same throughout the years.
Yes, you read this right.
Estimated Calorie Needs per Day
Our bodies are marvelous machines. They adjust our energy intake—the calories we need—based on many variables. The most widely known variables are age, sex, body weight, pregnancy, and hormonal status. But there are other variables that affect our caloric intake, including environmental temperature, energy expenditure, and dieting behaviors. And, yes, even transitioning from an agricultural economy to a manufacturing economy to an information-gathering sedentary society affected our energy need. (1)
In this article, we will explore how our caloric needs change over life— specifically after age 40.
Rise and Fall Of Calories Needed
Before we start our exploration a friendly reminder.
All numbers reflect estimated amounts of calories needed to maintain energy balance for various age and sex groups at three different levels of physical activity.
These estimates are based on the Estimated Energy Requirements (EER) equations, using reference heights (average) and reference weights (healthy) for each age-sex group. For adolescents, reference height and weight vary by age. For adults, the reference man is 5 feet 10 inches tall and weighs 154 pounds. The reference woman is 5 feet 4 inches tall and weighs 126 pounds.
From the time you are born through age 23 months, caloric needs increase by months instead of by years. This increase is vital for healthy growth and development. It is also the time period your body has the highest rates of energy expenditure per unit of body weight.
Starting at age 2 your body adjusts itself—now, energy needs increase/decrease by years instead of by months.
“A picture is worth a thousand words.”Adage
As you can see, for both sexes, calorie intake peaks in the second decade of life and declines thereafter.
The reference energy intake peaks are as follows:
- Female Energy Intake By Activity Levels
- sedentary: ages 19-20 with 2000 calories per day,
- moderately active: ages 19-20 with 2200 calories per day, and
- active: age 14 with 2400 calories per day.
- Male Energy Intake By Activity Levels
- sedentary: age 19-20 with 2600 calories per day,
- moderately active: age 16 with 2800 calories per day, and
- active: age 16 with 3200 calories per day.
For all age groups, except the baseline age of 2 years old, with 1000 calories, males had higher total caloric intakes than females.
Calories Per Day For Women
Based on the aforementioned information, you may ask, “so, what happens after the caloric peak times?”
Before we get started, it is noteworthy to mention for adult females (19+), the overall estimated calorie needs range from and 1,600 to 2,400 per day.
Further, while the focus of this article is on the reference intakes after age 40, we need to look at the overall decrease in energy intake as well.
You already know that the last increase for females is a) age 14 for active females with 2,400 calories per day, and b) age 19-20 for sedentary and moderately active females with 2000 and 2200 calories per day respectively.
According to research studies, the reference energy intake needed to maintain your weight in subsequent decades is as follows.
The first drop occurs between age 26-30 for sedentary and moderately active females and remains stable through age 50.
For active females, the first drop occurs between ages 31-35, and caloric intake and remains stable through age 60.
To maintain their weight…
- Sedentary women between the ages of 26-50 require about 1800 calories per day.
- Moderately active women between the ages of 26-50 require about 2000 calories per day.
- Active women between ages 31-60 require about 2200 per day.
Did you notice the difference in onset of peak and the length of time for active women? The length of time is 30 years compared to 25.
On paper, these differences don’t look insignificant—2200 kcal compared to 1800 for sedentary, and 2200 kcal compared to 2000 for moderately active females. But, when it comes to what and how much you can eat without gaining weight there is a huge difference. For example, an active female can enjoy that Shipley (360 kcal) or Krispy Kreme (400 kcal) donut without feeling guilty. The sedentary female, on the other hand, has to find a way to make up for the 400 kcal difference—either eat less or increase activity levels for the rest of the day.
Hence, it truly pays to maintain an active lifestyle throughout life.
What happens if you don’t
Well, we all know what happens if we don’t adjust our calorie intake based on our current lifestyle choices.
Most likely, WE GAIN WEIGHT!
Let’s look at an example.
If you are 26 old, live a sedentary lifestyle, and resume eating 2000 calories per day (peak years: 19-25), instead of 1800 (decreased years: 26-50), you, most likely, will gain weight.
Based on research we know it takes 3500 calories to gain/lose one pound. Therefore, if you consume 200 calories more per day for seven days, you overate by 1400 calories per week. This translates to an extra 0.4 pounds in the first week, everything else remains constant ( 1400 excess/3500=0.4 pounds). In a month, you would gain about 1.5 (1.6) pounds, and in a year about 19.2 pounds. Note: calculations are not adjusted for BMR (basal metabolic rate) and actual weight gain will be lower over.
Regardless of adjustment for BMR, this looks scary!
The second decrease of calories needed by age occurs between ages 51-55 for sedentary and moderately active and age 61-65 for active females.
For sedentary and moderately active females the second decrease in calories remains stable through age 76+.
For active females, as you already know, the second decrease doesn’t happen until ages 61-65 and also remains stable through age 76+.
In terms of energy intake
- Sedentary women between the ages of 51-76+ require about 1600 calories per day to maintain their weight.
- Moderately active women between the ages of 51-76+ require about 1800 calories per day to maintain their weight.
However, active women between the ages of 61-76+ still can eat about 2000 calories per day without gaining weight. This is the same amount of calories that our moderately active female could eat between ages 26-50. It is also the number of calories the sedentary female could only enjoy between ages 19-25.
Just looking at these numbers hopefully makes some of you jump off the chair and start to move more.
Calories Per Day For men
For adult males (19+), the overall estimated calorie needs range from and 2,000 to 3,000 per day.
And, compared to females, the energy intake adjustments are a little more scattered.
Again, we need to look at the overall increase and decrease in energy intake as well.
You already know, for males caloric intake peaked at age 19-20, with 2600 calories, for sedentary individuals. For moderately active and active males the peak occurred at age 16, with 2800 and 3200 calories per day respectively.
But now things get interesting.
Energy intake changes for males, for the most part, follow a unique 20-year pattern.
But, there is one exception.
All males regardless of lifestyle get an energy increase at age 16. For moderately active and active males, this increase marks their peak year. However, the sedentary male enjoys its peak at ages 19-20 with 2600 calories per day while his active counterpart experienced his first decrease.
Between Ages 21-40
While our sedentary male enjoys his last increase at ages 19-20, he is also the first to experience a decrease at ages 21-25. This decrease sets him back to the same calorie allowance of 2400 calories per day as he enjoyed during ages 16-18 and lasts through age 40.
The moderately active male experiences his first drop between ages 26-30 and remains stable through age 45. His energy requirement is about 2600 calories per day.
For active males, another second drop in energy intake occurs between ages 36-40. His energy allowance of 2800 calories per day remains stable through age 55.
Between Ages 41-60
The second decrease for the sedentary male occurs between ages 41-45. His energy requirements drop from 2400 to 2200 calories per day and remain stable through age 60.
The moderately active male experiences his second drop between ages 46-50. His energy intake allowance drops from 2600 to 2400 calories per day and remains stable through age 65.
The second (i.e. third) drop for active males in energy intake occurs between ages 56-60. The energy requirement drops from 2800 to 2600 and remains stable through age 75.
Between Ages 61-76+
The third and final decrease in caloric intake starts at ages 61-65 for sedentary males, ages 66-70 for moderately active males, and age 76+ for active males. The adjusted energy requirements are 2000, 2200, and 2400 respectively, and remain stable through the later years.
Did You Notice the pattern?
At first glance, the graphs above—first decrease and second decrease— look the same. But on closer inspection, you will notice the difference in age groups.
If we were to place the graphs over each other, we can with confidence say that energy intakes for males drop every 10 years and follow a 20-year cycle and then are repeated. The exceptions to the rule are the earlier and later life stages. For example, for active males, the 10-year drop pattern actually started at ages 19-20 and the last drop in calorie intake occurs at age 76+ down to 2400 calories per day.
By now, you have the answer to why you gain weight by eating the same calories per day as you did in your 20s.
Estimated energy intake requirements are different for females and males. As shown, males generally require more calories than females.
Adult (ages 19-20+) estimated calorie needs range from 1,600 to 2,400 calories per day for females and 2,000 to 3,000 calories per day for males. As shown, males generally require more calories than females.
Females need to adjust their energy intake levels two times based on age. Males, however, need to adjust their energy intake levels three times based on age.
Remember, all values are estimated calorie needs by age. To determine your needs, ask your physician or use one of the many online calculators available today
Always consult a medical professional before starting any diet.