How Many Calories Should You Eat Based on Age? Calculate Your Needs to Lose, Gain, or Maintain Weight

There are many diets that recommend a set number of calories. But actual calorie needs vary from person to person, and even day to day. The right number of calories for you depends on many factors, including your age and goals. 

Because of this, for many people, one-size-fits-all calorie goals often feel like a mismatch. They can result in harmful restriction, extreme hunger and fullness, and time-consuming calorie counting. And they don’t help you meet your health goals. 

So if you’re wondering how many calories you should eat a day, we’re here to help. In this article, we provide information that will allow you to match your calorie intake more closely to what your body needs. 

How does age affect how many calories you should eat a day?

Many people assume that their metabolism will naturally slow with age, and so they should eat fewer calories as they get older. But there’s a lot more to the story.

“Aging changes the way your body uses energy and calories,” said Dalia Perlman, RD, CDE, a research dietitian at Stanford University and science adviser for the January health app.

Perlman said that the following age-related factors affect your calorie needs: 

• Changes in your mitochondria, the energy-producing factories inside your cells

• Changes in your microbiome, the bacteria in your gut that aid digestion

• Dropping hormone levels

• New or evolving health conditions

• Medications  

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But these changes often don’t add up to a significant drop in basal metabolic rate (BMR) — the number of calories someone burns at rest. BMR remains relatively stable between the ages of 20 and 60. After age 60, BMR declines by about 0.7% each year. To put that in perspective, if someone had previously burned 2,000 calories a day at rest, a 0.7% drop would amount to about 14 fewer calories a day. There are fewer calories in a carrot. 

Still, many middle-aged adults will tell you that they eat less food as they get older — and the scale keeps climbing. That’s likely because their physical activity levels have dropped, said Jason Levee, MS, RD, CDN, a registered dietitian with Whole Family Health CO in Manhattan.

“We used to think that aging was directly related to middle- and late-life weight gain,” Levee said. “More recently, however, we’ve realized that weight gain mostly stems from declining activity levels.”

Levee explains that when people are young, they often have more free time to be physically active. But as people age, their increased responsibilities eat into that free time. He paints a picture of midlife and beyond that’s familiar to many people:

• Work stretches beyond 8 hours. 

• Commutes get longer. 

• Pastimes like online scrolling, TV watching, and gaming become a comforting escape.

• Family responsibilities lead to even more sitting time, especially for parents who are shuttling kids to school, sports, and other activities. 

• When the kids are grown and free time opens up again, people find that their joints hurt. Or, they may have other health issues that prevent them from exercising. 

The end result is that many people who are middle-aged and older are sedentary for 11 hours of a day, not including the time they spend sleeping.

Calorie intake recommendations by age

Even though everyone’s calorie needs will be different, it helps some people to have a general idea of how many calories their body needs a day.

To develop a personalized calorie goal, there are ways to calculate the average number of calories your body needs at rest to maintain your weight. Many healthcare professionals use the Mifflin-St. Jeor Equation: 

• Females: (10 x weight [kg]) + (6.25 x height [cm]) – (5 x age [years]) – 161

• Males: (10 x weight [kg]) + (6.25 x height [cm]) – (5 x age [years]) + 5

For example, based on the above formula, a 50-year-old woman who weighs 145 lbs (66 kg) and stands 5 ft 4 inches tall (163 cm) would burn roughly 1,268 calories at rest. 

But this equation doesn’t include physical activity, which can burn hundreds to thousands of additional calories. So the National Academies of Sciences, Engineering, and Medicine published a more comprehensive set of formulas that takes physical activity into account. Like the equations above, these equations also require some math. But they provide slightly more accurate estimates than precalculated charts.

Just a note that, if you use the equations in the chart below, keep in mind that:

• Age is in years.

• Height is in centimeters.

• Weight is in kilograms.

For men:

For women:

The National Institutes of Health (NIH) offers a free calculator that will do the arithmetic for you.

But no calculator is perfect, Levee said. For example, even the NIH calculator doesn’t take body composition into account. For example, someone with a higher percentage of muscle is going to require more energy — both at rest and during movement. 

It’s also important to remember that your calorie needs vary from one day to the next, Levee said. This depends on many different factors, such as sleep, hormone levels, and activity levels.

So think of your calorie goal as a rough estimate rather than a number you must reach every day with precision. 

How much to eat based on your goals

Levee doesn’t recommend people follow strict calorie goals, regardless of whether they’re trying to gain, lose, or maintain weight. 

There are several problems with calorie tracking. It can:

• Require a lot of time and effort

• Get in the way of listening to your natural hunger and fullness cues 

• Lead to accidental over- or undereating

Calorie-counting guides can also be inaccurate. For example, one guide may tell you that one medium apple contains about 100 calories. But medium apples vary in size and sweetness. As a result, one apple might truly contain anywhere from 80 calories to 110 calories, Levee said. These slight caloric differences can add up to hundreds of calories daily. 

This is why Levee recommends the following four-step process instead of calorie counting. 

Step 1: Log what you eat

Before changing what or how much you eat, it’s helpful to know your starting point. A good place to start is by keeping a food journal.

“Figure out what your current diet looks like most of the time, not including outliers like holidays,” Levee said. 

Keep track of everything you eat for 1 week. After gathering a week of data, you can move on to the next step.  

Step 2: Make some changes

Take a look at your food log. Based on this confirmation, try to get a round estimate of how much you’re getting of each nutrient:

• Fiber: Most people consume about half of what they need. Experts recommend 25 g to 38 g a day for good health and weight maintenance, Levee said.

• Protein: Like fiber, many people don’t get enough. And too little protein can leave you hungry. It can also affect your ability to maintain muscle mass, Levee said. For people trying to gain muscle, Levee said that 1.5 g of protein per kilogram of body weight is a good goal. 

• Sugar and starch: This is an area where most people overdo it, Levee said, which leads to unwanted weight gain. The Dietary Guidelines for Americans recommend capping added sugar to no more than 10% of your overall food intake. 

• Fat: Similar to starch, many people would benefit from scaling back, Levee said. Or focus on tipping the balance toward healthy fats. Limit fat intake to less than 35% of your total food intake by using the “plate method” (below). 

• Ultra-processed food: Ideally, you want most of what you consume to come from nutrient-dense, minimally processed foods. 

The “plate method” offers an easy way to put the above suggestions into practice. No matter what your weight goals are, try to fill your plate:

• half with vegetables

• a quarter with lean protein

• the rest with fibrous carbohydrate foods like winter squash, fruit, legumes, or whole grains

Step 3: Check in with your hunger

The best way to know what your body actually needs is to listen to your natural hunger and fullness signals. 

To tune into these sensations, Levee recommends that you try to eat slowly and without distractions.

Before digging in, check in with your hunger using a scale from 1 (starving) to 10 (stuffed). Ideally, your hunger will be somewhere between a 4 (stomach is growling) and a 5 (a little hungry but not full). If it’s higher than a 5, you might be eating for some other nonhunger-related reason — boredom, stress, or convenience, for example.

Then, check in a few more times as you eat. See if you can stop eating when you’re around a 6 (satisfied, but not yet full) or 7 (full, but not uncomfortable). 

Over time, as you become more in tune with these natural cues, you can use this information to reach your goals.

• For fat loss: Stop eating when you’re about 80% full, which is around a 6 on the scale.

• For muscle gain: Experiment with eating a little more, perhaps to about 7 or 8 on the scale.

• For maintenance: Split the difference, stopping between a 6 and a 7. 

Step 4: Weigh yourself at regular intervals 

Monitoring body weight or measurements can help you see whether your food intake is helping you reach your goals. But know that weight naturally fluctuates from one day to the next. So Levee recommends that you pay more attention to an overall trend rather than get caught up in the number of just 1 day. 

If you’re trying to lose weight, but you’re not seeing any results after a few weeks, you might try:

• Making small adjustments to your portions

• Allowing yourself to feel a little less full at the end of meals

• Adding more low-calorie vegetables and fewer higher-calorie starches to your plate

If you’re trying to gain muscle, you could try to:

• Boost the amount of protein on your plate

• Challenge your muscles with strength training 

Advice for older adults

It can be hard for older adults to eat enough food to maintain weight and muscle mass. This is often related to natural changes in appetite or enjoyment of food. But older adults often need a higher weight than younger people to stay healthy and mobile.

If you’re struggling to keep on weight, talk with a healthcare professional. They can help rule out health conditions and medications that can affect weight and appetite. 

Levee also recommends the following: 

• To stimulate appetite, try to move a little more. You might, for example, add a short daily walk or join a group fitness program for older adults. 

• Consider ways to add just a little more protein to your meals. Increase the portion size of protein foods you still enjoy. Or, try a protein drink or smoothie. 

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Written by:

Alisa Bowman

Alisa Bowman got her start as a general assignment reporter for a large, metropolitan newspaper. She later worked for Rodale Books and Runner’s World magazines.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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