Why Not Eating Enough Can Make PCOS Symptoms Worse

What happens in your body when you restrict calories or skip meals

There’s something I find myself saying almost daily in my work with women with PCOS:

Around 99% of the women who come to work with me are not eating enough, regularly - and this is often making their PCOS symptoms worse.

Before anything else, I want to be really clear about something.

This isn’t about guilt or blame. And it’s definitely not a lack of willpower.

I completely understand why this is happening.

Most advice given to women with PCOS is still centred around:

• weight loss

• cutting carbohydrates

• eating less

• being more disciplined

I lived this myself.

When I was first diagnosed with PCOS, I was put on a 1200-calorie diet. It was awful. I was hungry all the time, constantly thinking about food, and my symptoms didn’t improve.

So today, I want to explain what actually happens in your body when you restrict food - whether that’s by skipping meals, eating low calories, or both - and why this creates the restriction–rebound loop so many women with PCOS feel stuck in.

Restricting calories or skipping meals sends the same signal to your body

From a physiological perspective, skipping meals and not eating enough send the same message to the body:

Energy is not reliably available.

This state is known as low energy availability.

It doesn’t matter whether:

• you skip breakfast

• 
  

  you delay eating until late afternoon

• you eat regularly but your portions are very small

• you cut out entire food groups like carbohydrates

  
  

Your body responds in very similar ways.

What happens in your body when you don’t eat enough

When the brain senses that energy intake is insufficient, it activates defence systems designed to keep you alive.

Hunger hormones increase and “safety” signals decrease

Research consistently shows that short-term energy restriction in women:

• increases subjective hunger - meaning you feel hungrier and think about food more often

• lowers leptin, a hormone that helps signal “I’m full, we’re okay”

• increases appetite-stimulating hormones like ghrelin and orexin, essentially turning the volume up on hunger(Shekhar et al., 2020)

  
  

Leptin dropping is particularly important.

Low leptin tells the brain:

Energy stores are under threat. We need to eat.

This signal alone increases food focus and motivation - often before hunger feels extreme.

Stress hormones rise to protect blood sugar

When food intake is delayed or insufficient:

• the body relies more heavily on stress hormones like cortisol

• these hormones help keep blood sugar stable by releasing stored energy

  
  

This is helpful in the short term.

But when it happens repeatedly, it:

• increases hunger

• increases cravings

• makes blood sugar regulation harder

• contributes to worsening insulin resistance over time

  
  

This is especially relevant for women with PCOS, where insulin regulation is often already more fragile.

Why hunger and cravings often get worse later in the day

As restriction continues across the day:

• hunger hormones stay elevated

• fullness hormones become less responsive - meaning it takes more food to feel satisfied

• the brain becomes more sensitive to rewarding foods, especially sugary and carbohydrate-rich foods

  
  

What this can feel like in real life:

• eating a large evening meal but still feeling hungry

• feeling like food “doesn’t hit the spot”

• having a strong pull toward quick-energy foods

  
  

Studies show that after skipping meals or prolonged restriction:

• GLP-1 and PYY (hormones that help you feel full) are blunted at the next meal - this is why even after a big dinner you might still feel hungry

• insulin responses are exaggerated, meaning blood sugar rises and falls more sharply

• reward centres in the brain respond more strongly to highly palatable foods like chocolate, biscuits, bread, or sugary snacks(Thomas et al., 2015; Gwin & Leidy, 2018)

Together, this makes it:

• harder to feel satisfied

• easier to keep eating

• more likely to crave quick-energy foods like carbohydrates and sugar

  
  

This is not a lack of control - it’s a predictable biological response.

“But I eat regularly” - why low-calorie eating still drives hunger

Some women tell me:

“I don’t skip meals — I eat regularly.”

And that does matter. Regular meal timing helps.

Research shows that eating at consistent intervals:

• improves feelings of fullness

• reduces sharp hunger swings

• supports the release of fullness hormones (Alhussain et al., 2016; Alhussain et al., 2021)

  
  

However, when overall intake remains too low, the body still experiences energy deprivation.

Studies on low-calorie diets show:

• hunger often remains high

• leptin levels stay reduced

• the biological drive to eat continues

• appetite doesn’t meaningfully settle over time (Triffoni-Melo et al., 2023; Malin et al., 2020)

So even with regular meals, the background message is still:

We need more energy.

Higher-fibre, higher-volume meals can smooth hunger and reduce sharp rebounds - but they can’t fully override the body’s need for adequate energy(Buckland et al., 2018; Hannon et al., 2021).

And then comes the guilt - and the loop continues

Eventually, hunger wins.

You eat - sometimes a balanced meal, sometimes something sugary - in response to what your body is asking for.

And then many women think:

• “I messed up.”

• “I can’t trust myself.”

• “I need to be stricter.”

  
  

So restriction starts again.

And the cycle repeats.

Over time, rigid restriction combined with stress and negative emotion is strongly associated with loss-of-control eating patterns (Casari et al., 2025; Baenas et al., 2023).

How to break the restriction–rebound cycle with PCOS

Breaking this cycle doesn’t mean eating without structure.

It means supporting your biology.

1. Eat enough, regularly

Skipping meals and chronic under-fuelling drive this loop.

A gentle starting point:

• eat every 3–4 hours during the day

• prioritise adequacy before optimisation

2. Build meals that actually satisfy

Meals that reduce rebound hunger usually include:

• protein

• fibre-rich carbohydrates

• fats

This supports fullness hormones and steadier blood sugar.

3. Stop blaming carbohydrates

Carbohydrates are often what the body is asking for when energy is low.

Including them regularly:

• reduces reliance on stress hormones

• supports blood sugar stability

• reduces urgency and intensity around food

4. Replace guilt with curiosity

Guilt keeps the loop alive.

Curiosity interrupts it:

• “Did I eat enough earlier?”

• “Did I delay meals?”

• “What might my body need more of?”

Key takeaway: skipping meals and not eating enough affect PCOS in the same way

From a biological perspective, skipping meals and eating too little are the same problem.

Both signal low energy availability. Both increase hunger and stress hormones. Both make rebound eating more likely.

Most women with PCOS are not eating too much. They’re eating too little, too irregularly, for too long.

This isn’t a discipline problem. It’s physiology.

And once you understand that, everything starts to make a lot more sense.

References

Alhussain, M., Macdonald, I. A., & Taylor, M. A. (2016). Irregular meal-pattern effects on energy expenditure, metabolism, and appetite regulation in healthy normal-weight women. The American Journal of Clinical Nutrition, 104(1), 21–32. https://doi.org/10.3945/ajcn.115.125401

Alhussain, M., Macdonald, I. A., & Taylor, M. A. (2021). Impact of isoenergetic intake of irregular meal patterns on thermogenesis, glucose metabolism and appetite: A randomized controlled trial. The American Journal of Clinical Nutrition. https://doi.org/10.1093/ajcn/nqab323

Baenas, I., Miranda-Olivos, R., Solé-Morata, N., Jiménez-Murcia, S., & Fernández-Aranda, F. (2023). Neuroendocrinological factors in binge eating disorder: A narrative review. Psychoneuroendocrinology, 150, 106030. https://doi.org/10.1016/j.psyneuen.2023.106030

Buckland, N. J., et al. (2018). A low energy–dense diet affects appetite control in women. The Journal of Nutrition, 148(5), 798–806. https://doi.org/10.1093/jn/nxy041

Casari, M., et al. (2025). Does restriction lead to binge eating? Nutrition Reviews. https://doi.org/10.1093/nutrit/nuaf163

Gwin, J. A., & Leidy, H. J. (2018). Breakfast consumption vs skipping and appetite regulation. Current Developments in Nutrition, 2(7). https://doi.org/10.1093/cdn/nzy074

Hannon, S., et al. (2021). Lower energy-dense meals and appetite ratings. Nutrients, 13(12), 4505. https://doi.org/10.3390/nu13124505

Levitsky, D. A., & Pacanowski, C. R. (2013). Effect of skipping breakfast on subsequent energy intake. Physiology & Behavior, 119, 9–16. https://doi.org/10.1016/j.physbeh.2013.05.006

Malin, S. K., et al. (2020). Hunger during caloric restriction in women. Physiology & Behavior, 223, 112978. https://doi.org/10.1016/j.physbeh.2020.112978

Shekhar, S., et al. (2020). Energy deprivation and metabolic hormone responses. Journal of the Endocrine Society, 4(Suppl 1). https://doi.org/10.1210/jendso/bvaa046.1468

Thomas, E. A., et al. (2015). Breakfast skipping and appetite regulation. Obesity, 23(4), 750–759. https://doi.org/10.1002/oby.21049

Triffoni-Melo, A. T., et al. (2023). High-fiber diets during caloric restriction. Arquivos de Gastroenterologia, 60(2), 163–171. https://doi.org/10.1590/S0004-2803.202302022-96

Zeballos, E., & Todd, J. E. (2020). Skipping meals and diet quality. Public Health Nutrition, 23(18), 3346–3355. https://doi.org/10.1017/S1368980020000683

This article is intended for educational purposes and does not replace individualised medical or nutrition advice. If you’re unsure how much or how often to eat with PCOS, working with a qualified health professional can help.