How to manage your weight after 40

Some people find it tougher to maintain a healthy weight after they turn 40. This might stem from factors like hormonal and metabolic changes and decreasing muscle mass.

Everyone’s body is different, so a unique range of factors could make weight gain more likely for you in your 40s and beyond. 

But if weight management is part of your health goals, it’s achievable. Eating well, making space for exercise in your routine, and getting enough sleep can all help.

Why is weight management harder in your 40s?

As you move through and past your 40s, changes in your body can make managing your weight more challenging. We’ll look at some of these changes below.  

Metabolic changes

Your metabolism is the process of your body getting energy from food. And changes to this process can affect how easy it is to gain or lose weight. 

The way that you metabolize food changes as you age, particularly if you’re female. 

ZOE’s own research shows that men tend to have higher post-meal blood sugar rises than women early in life. But as women get older, their post-meal blood sugar levels tend to get larger. 

Data collected by ZOE scientists show that, on average, women experience larger post-meal blood sugar spikes as they get older.

Still, these changes are individual — they depend on how well your body is able to metabolize foods that contain carbs. Another term for this is: blood sugar control

With ZOE’s at-home test, you'll learn about your blood sugar control and how well you metabolize fat. You'll also find out about the state of your gut microbiome. Based on all of this information, you'll learn how to eat for your best health with a personalized nutrition program.

Take our free quiz to learn more. 

Muscle loss

Muscle mass naturally declines as we age, and this can lead to a slower metabolism.

When your metabolism slows, your body burns fewer calories at rest, making it harder to lose weight.

This can all stem from a combination of factors, including a sedentary lifestyle, diet factors, chronic health conditions, and genetics. 

Changes in hormone levels over time might also affect your muscle mass and other aspects of your body composition as you move past your 40s.

For example, the levels of two hormones called growth hormone and insulin-like growth factor 1 increase in our bodies until we hit puberty. Then, they slowly decrease by about 1–2% each year. As these levels drop, so does our muscle mass.

Meanwhile, dehydroepiandrosterone (DHEA) is a steroid hormone that helps the body make other hormones, including sex hormones. 

Levels of DHEA decline by about 2–3% each year after a person reaches their 30s. Lower DHEA levels are linked to lower muscle mass and increased body fat. 

Hormonal changes in men

Testosterone is a sex hormone that plays a role in regulating metabolism and maintaining muscle mass. 

A 2022 review explains that testosterone levels decrease by 1–2% every year after males reach 30–40 years of age.

Lower testosterone levels can lead to a decrease in muscle mass and an increase in body fat.

Hormonal changes in women

Menopause and the stage leading up to it, called perimenopause, involve a range of hormonal changes. As a result, your body composition and where your body stores fat can also change.

For women in their 40s, a decrease in the production of the hormones estrogen and progesterone can contribute to weight gain.

Estrogen helps regulate body weight by affecting fat storage and metabolism. Decreasing levels of estrogen can contribute to an increase in body fat, particularly in your abdomen.

Looking beyond hormones, weight gain during menopause can also stem from lifestyle and environmental changes that are happening at the same time.

Lifestyle factors

It’s important to remember that changes relating to hormones, metabolism, and muscles affect everyone differently. 

But generally, we tend to become less active as we age, which can contribute to weight gain. Our diets and eating habits also tend to change over time. 

According to the National Institute on Aging, here are other factors that can affect weight management as we get older: 

The good news? You can do plenty to maintain a healthy weight in your 40s and beyond.

Tips for reaching a healthy weight

In your 40s, your body might be priming itself to gain weight quicker or store fat in different places. 

However, you can take steps to manage your weight and prevent some risks associated with obesity, like diabetes and heart disease.

1. Eat well

How your diet and eating habits affect your weight can change with time.

If you’re in your 40s, figuring out what foods are best for you can help you manage your weight. These foods might be different from what you ate earlier in your life.

If you want to know how your body responds to food and how a personalized nutrition program can help you eat for your health and weight goals, start by taking our free quiz.

You might be surprised to learn that calorie counting doesn’t work for sustained weight loss. So, rather than only focusing on your energy intake, it’s a good idea to focus on the quality of your food.

With this in mind, these strategies may help you manage your weight:

  • Pile on the fruit and veg. They fill you up, contain beneficial compounds, and reduce the risk of diseases. Prof. Tim Spector recommends aiming to eat 30 different plants a week.

  • Switch to whole grains. Eating whole grains supports weight management and reduces inflammation while supporting your gut microbiome, according to a small 2019 study.

  • Create a protein-rich diet. A 2016 study found that a high-protein diet helped older adults maintain muscle and lose fat. High-protein foods include lean meats, fish, legumes, seeds, and nuts.

  • Eat fewer ultra-processed foods. These products can leave you still feeling hungry. They often contain lots of added sugars and few nutrients. So, whenever possible, swap out ultra-processed foods for less processed or minimally processed options.

2. Stay active

Children, work, and life in general can keep you busy in and after your 40s. As a result, finding time to exercise might be challenging.

Although exercise alone may not help you reach a healthy weight, it can play an important part in maintaining weight loss. It also has a wide range of other health benefits.

The Physical Activity Guidelines for Americans recommend that adults get 150–300 minutes of moderate aerobic exercise or 75–150 minutes of vigorous exercise every week. 

It’s worth keeping in mind that you don’t have to start with gym sessions or runs. Gardening, dancing, taking Fido for a walk, or simply taking the stairs instead of the elevator can all boost your activity levels.

Getting a friend involved or joining an exercise community, like a walking group or swimming club, can make it fun and help you maintain it in the long run.

3. Set realistic goals

Research shows that setting targets is an important way to develop healthy behaviors that support weight management. 

But we’re only human, and trying to achieve too much too quickly is unsustainable. This can also be dangerous when it comes to weight management.

According to the Centers for Disease Control and Prevention (CDC), a sustainable target for weight loss involves losing 1–2 pounds a week.

The CDC also suggests a realistic goal of losing 5–10% of your current body weight in the long term. 

After achieving this weight loss, people with overweight or obesity are likely to have a reduced risk of heart disease and diabetes.

But there’s no “right” end goal — except the one that’s right for your body. Speak with a doctor or dietitian about a healthy target range and how long it should take to get there. 

4. Focus on sleep

Given our hectic schedules, sleep often doesn’t get the space in our lives that it deserves. But sleep is important

ZOE’s own research has shown that a bad night’s sleep leads to poorer blood sugar responses the next day. This means that you’re more likely to have blood sugar spikes after eating.

Blood sugar spikes are linked to increased hunger, among other effects. And in the long run, they can also increase the risk of developing obesity. 

The research also found that going to bed earlier is better than trying to catch up by sleeping in. 

5. Consider intermittent fasting

Time-restricted eating is the most popular type of intermittent fasting

It involves eating during a specific time window each day. So, you might only eat between 9 a.m. and 7 p.m., for example. 

So, rather than focusing on what you eat, you focus on changing when you eat, while still having an overall healthy diet.

Several short-term, small studies have found that intermittent fasting can support healthy weight management, leading to losing 0.8–13% of body weight without serious side effects. 

However, intermittent fasting doesn’t seem to lead to more weight loss than other diets. Ultimately, it’s about figuring out what works best for you. 

ZOE is running the largest time-restricted eating study in the world — the Big IF study. We want to understand how it affects people’s mood, energy levels, hunger, and symptoms of health conditions.

6. Forgive, adjust, and stay positive.

Managing your weight is more challenging in and after your 40s. You may not get it right the first time, and some days will be harder than others.

But you’re making decisions to keep up your health, and that’s a huge step in the right direction. You won’t see the results unless you stick with it. So, practice a little self-forgiveness, and try again the next day.

And if the results aren’t quite where you expected, try to adjust your goals so that they’re more realistic and comfortable, and keep pushing toward them.

If you have the resources, get support from a dietician and try joining a gym group, taking guided classes, or hiring a personal trainer. 

An experienced guide can help you manage your weight without anything feeling like a punishment.


After 40, your body finds it easier to gain weight. This stems from a range of factors, including metabolic changes, hormone shifts, and muscle loss, alongside lifestyle factors and genetics.

Finding fun ways to exercise and having a healthy, diverse diet is important. When it comes to food, quality is key.

Forget calorie counting and focus on including a diverse range of plant foods in your diet. Time-restricted eating might also help.

It’s important to set realistic, sustainable goals, move ahead with forgiveness, and make room for sleep and exercise in your routine. 

At ZOE, we know that everyone responds to food differently. That’s why our program helps you choose the foods that suit your body and move toward your long-term health goals. 

Our program also provides ongoing support from qualified nutritionists to help you make the best choices for your body.

Take this free quiz to find out how ZOE can support your health journey.


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Setting targets leads to greater long‐term weight losses and ‘unrealistic’ targets increase the effect in a large community‐based commercial weight management group. Journal of Human Nutrition and Dietetics. (2016). 

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