Why Am I Gaining Weight During Perimenopause?

At a Glance

• Weight changes during perimenopause are common, but they are not caused by hormones alone.
• Hormonal fluctuations may contribute to an increased accumulation of abdominal fat.
• Aging, sleep changes, stress, physical activity levels, and the gradual loss of muscle mass also play a role in these changes.
• Muscle mass plays an important role in metabolic health, mobility, and maintaining independence as we age.
• Regular physical activity, particularly strength-training exercises, along with a balanced diet and quality sleep, can help support overall health during this transition.

Many women notice changes in their weight or body shape in their forties, sometimes even though they have not changed their eating habits or level of physical activity.

Some find that their weight gradually increases. Others notice a greater accumulation of fat around the abdomen, despite never having tended to gain weight in that area before.

These changes can be frustrating and may lead many women to wonder: is this simply a part of aging, or does perimenopause play a role?

The answer is nuanced. Hormonal changes associated with perimenopause can influence body composition, but they are only one part of the picture.

Does Perimenopause Actually Cause Weight Gain?

Research suggests that the weight gain commonly observed during midlife is primarily related to the natural aging process rather than perimenopause itself.

However, hormonal fluctuations appear to promote a redistribution of body fat toward the abdominal region. As a result, even when total body weight changes very little, many women notice that their clothes fit differently or that their body shape changes.

In other words, it is not only a matter of the number on the scale, but also of body composition.

Why Does the Body Change After 40?

Several factors contribute to the changes that occur during this stage of life.

Hormonal Changes

Estrogen influences several mechanisms related to metabolism, appetite, and fat distribution. As hormone levels become more variable, some women notice an increased accumulation of abdominal fat.

Sleep Often Becomes More Difficult

Nighttime awakenings, night sweats, and insomnia are common during perimenopause.

Insufficient sleep can affect the hormones that regulate appetite, increase cravings, and reduce the energy available for physical activity throughout the day.

Stress and Mental Load

The forties are often a period when many responsibilities overlap: career demands, children, aging parents, and other personal obligations.

Chronic stress can influence eating habits, sleep, and overall health.

The Gradual Loss of Muscle Mass

This is a factor that receives less attention but plays an important role.

Beginning in the thirties and forties, muscle mass gradually declines if it is not actively maintained. Because muscle is metabolically active tissue, this loss can contribute to a gradual reduction in energy expenditure over time.

This is one reason why some women feel that strategies that worked well in the past no longer produce the same results.

Why Does Muscle Mass Become So Important?

When discussing weight, the focus is often placed entirely on body fat.

However, muscle mass plays a vital role in overall health.

It helps to:

• Maintain strength and mobility
• Support metabolism
• Improve balance and reduce the risk of falls
• Preserve bone health
• Facilitate daily activities

During perimenopause and after menopause, maintaining muscle mass becomes an important goal—not only for weight management, but also for long-term health.

What Can You Do?

There is no miracle solution and no one-size-fits-all approach. However, certain habits can help support metabolic health and body composition.

Incorporate Strength Training

Resistance exercises, such as training with free weights, resistance bands, or weight machines, help stimulate and maintain muscle mass.

You do not need to become an athlete. Even a few sessions per week can provide meaningful benefits.

Stay Physically Active

Walking, cycling, swimming, and other forms of physical activity contribute to cardiovascular health and overall well-being.

Pay Attention to Protein Intake

Protein plays an essential role in maintaining muscle mass. Nutritional needs vary from person to person, but ensuring an adequate protein intake becomes particularly important during this stage of life.

Prioritize Sleep

Sleep affects recovery, appetite, energy levels, and metabolic health. Improving sleep quality can have benefits that extend far beyond reducing fatigue.

Take a Long-Term Approach

The changes that occur during perimenopause are often gradual. Extreme approaches and restrictive diets are rarely sustainable.

Realistic habits maintained over time generally have a greater impact on health than quick fixes.

Conclusion

The changes experienced during perimenopause can be unsettling, particularly when they occur despite lifestyle habits that seemed to work well in the past. Understanding the different factors involved can help foster a more realistic and sustainable approach.

Beyond the number on the scale, maintaining strength, mobility, and overall health becomes an important objective during this transition. Muscle mass plays a central role in this process and represents an important investment in health for the years ahead.

Looking Ahead

Muscle mass also plays a critical role in bone health, mobility, and maintaining independence as we age.

In an upcoming article, we will explore why maintaining muscle mass becomes especially important after age 40, along with strategies that can help preserve strength and bone health during perimenopause and menopause.

References and Further Reading

1. Fenton, A. (2021). Weight, shape, and body composition changes at menopause. Journal of Mid-life Health, 12(4), 297–304. https://pmc.ncbi.nlm.nih.gov/articles/PMC8569454/

2. Kodoth, V., Scaccia, S., & Aggarwal, B. (2022). Adverse Changes in Body Composition During the Menopausal Transition and Relation to Cardiovascular Risk: A Contemporary Review. Women's health reports (New Rochelle, N.Y.), 3(1), 573–581. https://doi.org/10.1089/whr.2021.0119

3. Isenmann, E., Kaluza, D., Havers, T., Elbeshausen, A., Geisler, S., Hofmann, K., Flenker, U., Diel, P., & Gavanda, S. (2023). Resistance training alters body composition in middle-aged women depending on menopause - A 20-week control trial. BMC women's health, 23(1), 526. https://doi.org/10.1186/s12905-023-02671-y

4. Shieh, A., Karlamangla, A. S., Karvonen-Guttierez, C. A., & Greendale, G. A. (2023). Menopause-Related Changes in Body Composition Are Associated With Subsequent Bone Mineral Density and Fractures: Study of Women's Health Across the Nation. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 38(3), 395–402. https://doi.org/10.1002/jbmr.4759