You’re eating well. You’re staying active. But the number on the scale keeps creeping up.
Before you blame your willpower, it might be worth looking at what your hormones are doing behind the scenes.
“Hormones help regulate how your body burns calories, manages hunger and stores fat, but they don’t work in isolation,” says Kelli Harper, DO, a bariatric medicine specialist with Hartford HealthCare Medical Group. “Weight regulation is complex, and hormones are just one piece of the puzzle.”
Here are four ways your hormones might be affecting your weight.
1. Thyroid problems
Your thyroid helps control how quickly your body uses energy. When it’s underactive (hypothyroidism), your metabolism slows down.
You might notice symptoms like:
- Fatigue.
- Feeling unusually cold.
- Constipation.
- Gradual weight gain.
“Weight gain from thyroid disease is usually modest and tends to develop slowly,” says Dr. Harper. “People often notice other symptoms beyond weight shifts, and a simple blood test can give us answers.”
> Related: Medical Reasons You Can’t Lose Weight (No Matter How Hard You’re Trying)
2. Hormone shifts in women
Estrogen, progesterone and testosterone all affect how your body stores and uses fat. For women, these hormones naturally fluctuate throughout their monthly cycle. And during perimenopause and menopause, the changes can be even more dramatic.
“Women’s hormones can make weight loss feel unpredictable,” says Dr. Harper. “Estrogen tends to promote fat storage around the hips and thighs, while testosterone helps support lean muscle.”
During menopause, declining estrogen can also shift fat storage toward the abdomen. “At the same time, muscle mass gradually decreases and metabolism slows slightly with age – making weight changes more common,” adds Dr. Harper.
> Related: Should I Try GLP-1s for Weight Loss?
3. Insulin resistance
Insulin helps move sugar from your bloodstream into your cells for energy. But when your body becomes resistant to insulin, it has a harder time using that sugar properly.
“When the body becomes resistant to insulin, it may store more fat – particularly around the abdomen,” says Dr. Harper.
This may be more common in:
- Prediabetes or type 2 diabetes.
- Metabolic syndrome.
- Polycystic ovary syndrome (PCOS).
“While weight loss can be more challenging with insulin resistance, it’s very manageable with the right tools and choices,” says Dr. Harper.
Want a Weekly Dose of Health News?
4. Stress and cortisol
Cortisol is the body’s primary stress hormone, and it’s helpful in short bursts.
“But when stress becomes chronic, cortisol can increase appetite, disrupt sleep and promote abdominal fat storage,” says Dr. Harper.
“Poor sleep can also throw off the hormones that control hunger and fullness. “If you’re aiming for a healthier metabolism, start with improving sleep and managing stress,” suggests Dr. Harper.
> Related: Why Men Lose Weight Differently Than Women
How to uncover what’s causing your weight gain
If your weight has been changing and you can’t figure out why, it may be time to take a closer look.
“We look at the full picture,” says Dr. Harper. “Lab work, lifestyle habits and symptoms all help us understand what might be driving weight changes. If something feels off, it’s worth having the conversation with your doctor so they can help you address it and start feeling better.”
Understanding the role of your hormones can help you make sense of your weight gain and decide your next step if something feels off.
