Are You Eating Enough for Your Hormones?

Why Undereating Can Make Midlife Hormonal Shifts Even Harder 

It’s one of the most common pieces of advice women hear when they start gaining weight in midlife: 

“Just eat less.” 

It sounds simple. Logical, even. If your pants are getting tighter and the scale is creeping up, cutting calories seems like the obvious solution. And for women in their 20s or 30s, sometimes it works, at least in the short term. 

But midlife is different. 

If you’re in your 40s or 50s and navigating perimenopause or menopause, the rules change. Undereating can actually make things worse, not just for your weight, but for your hormones, energy levels, mood, metabolism, sleep, and overall well-being. 

Let’s break down why eating too little can disrupt your hormonal balance, and what you can do instead. 

Undereating = Stress for Your Body 

When you don’t give your body enough food, especially over weeks or months, it goes into a state of stress known as low energy availability. This happens when the calories you eat aren’t enough to fuel both your basic bodily functions and your daily activity. 

In response, your body does what it’s designed to do: it conserves energy, shifts priorities, and begins downregulating systems that are not essential to short-term survival, including your reproductive, thyroid, and metabolic functions. 

In other words, your body starts turning down the dial on the very hormones that are already fluctuating in midlife. 

How Undereating Disrupts Hormones 

1. Sex Hormones: Estrogen & Progesterone 

• Reproductive shutdown: Your brain senses energy scarcity and suppresses the production of estrogen and progesterone. This survival mechanism, known as functional hypothalamic amenorrhea (FHA), often leads to irregular or missed periods. 

• Less body fat, less estrogen: Body fat helps convert other hormones into estrogen. Undereating reduces body fat, which can further diminish estrogen levels, compounding mood swings, hot flashes, and menstrual changes. 

• Worsening perimenopause symptoms: Midlife women already experience hormone fluctuations. When you underfuel your body, symptoms like night sweats, sleep disruptions, low libido, and mood instability can worsen. 

2. Stress Hormones: Cortisol 

• Cortisol rises in a calorie deficit: The body interprets undereating as famine, increasing cortisol production. 

• High cortisol = midsection weight gain: This can lead to belly fat storage, increased anxiety, and irritability. 

• Midlife sensitivity: With progesterone in decline during perimenopause, its naturally calming effect is reduced—making your system more reactive to cortisol and stress overall. 

3. Thyroid Hormones: T3, T4 

• Metabolism slows down: In energy conservation mode, the thyroid reduces production of T3, the hormone that keeps your metabolism humming. 

• You feel cold, tired, and gain weight easily, even if you’re eating less. 

• Nutrient deficiencies: Undereating often leads to low intake of iodine, selenium, and zinc, all vital for thyroid function. 

4. Hunger & Fullness Hormones: Leptin & Ghrelin 

• Low leptin = more hunger, less hormone regulation: As body fat drops, leptin levels fall. This makes you feel hungrier and throws off the balance of reproductive hormones. 

• High ghrelin = insatiable cravings: In response to the calorie deficit, ghrelin, your hunger hormone, increases, making it hard to feel full or satisfied. 

Overlapping Symptoms: Perimenopause or Undereating? 

This is where things get tricky. The symptoms of undereating often mirror those of perimenopause: 

• Fatigue 

• Brain fog 

• Mood swings 

• Insomnia 

• Irregular cycles 

• Weight gain (yes, even from eating less) 

That’s why so many women feel confused. You’re eating less but gaining weight. You’re working out more but feeling worse. You’re trying to do the “right” thing, but your body isn’t responding. 

The truth? You might not be eating enough. 

How to Restore Balance 

If this sounds familiar, the first step is to shift your mindset from restriction to nourishment. Your body isn’t broken; it’s asking for support. 

Here’s what that support looks like: 

• Eat enough to fuel your life. Especially if you’re active, busy, or under stress. 

• Prioritize protein. Aim for 0.7–1 gram per pound of your ideal body weight to support muscle, metabolism, and hormone production. 

• Don’t fear carbs. Especially complex carbohydrates like root vegetables, legumes, and whole grains, which help regulate cortisol and fuel thyroid function. 

• Incorporate healthy fats. Hormones are made from fat. Think avocado, olive oil, nuts, seeds, and omega-3 rich fish. 

• Listen to your hunger cues. Constantly ignoring hunger can disrupt your hormonal feedback loops. 

For the Active Woman: Watch for Low Energy Availability 

Women who exercise regularly, especially those doing cardio or intense strength training, are at even greater risk for undereating. If your training isn’t paired with adequate fuel, your body sees this as another stressor. 

Remember: Exercise is only beneficial if the body has the nutrients to recover and rebuild. 

The Bottom Line 

Midlife is not the time to starve yourself. 

Your body is going through enough already, fluctuating estrogen, rising cortisol, changing metabolic needs. The last thing it needs is a constant calorie deficit. 

Instead of eating less, eat smart. 

Instead of fearing food, nourish your body. 

Instead of pushing harder, listen deeper. 

Supporting your hormones starts with giving your body what it needs to thrive.