Why is it so hard to lose weight with PCOS (PMOS)?

PCOS often comes with insulin resistance and higher androgen levels, which make it easier to store fat and can affect appetite. It is a hormonal and metabolic challenge, not a lack of willpower.

What is the best diet for PCOS weight loss?

The 2023 international PCOS guideline found no evidence that any one diet is better than another. A modest energy deficit in a balanced way of eating you can keep up, with fibre, protein and unsaturated fats, works best. Very restrictive diets often backfire.

How much weight do I need to lose to improve PCOS?

For women with a higher weight, losing 5 to 10% of body weight can improve cycles, ovulation, insulin and cholesterol. Healthy habits also improve PCOS without any weight loss.

Losing Weight with PCOS/PMOS: What Helps

Losing weight with PCOS, now officially renamed PMOS, is often slower because the condition changes how your body handles insulin and hormones. If the scale won't move no matter what you try, you're not imagining it. It is not a willpower problem, and it is not impossible.

You probably already know the basics: eat well, move more. What's harder is knowing which advice actually holds up for PCOS. As a registered dietitian who works with women with PCOS every day, here's what the research, including the 2023 international PCOS guideline ^[1], says really helps.

Why is weight loss harder with PCOS?

PCOS/PMOS is a hormonal and metabolic condition, not just an ovary problem. Three things work against you:

Insulin resistance. It is a core feature of PCOS, including in many women who are not at a higher weight. Higher insulin levels make it easier to store fat. Read more in my guide to insulin resistance, weight and hormones.
Higher androgens. Insulin drives the ovaries to make more androgens (such as testosterone), and androgens can worsen insulin resistance in turn.
Appetite. Some studies suggest differences in hunger and fullness hormones in PCOS, though this research is still developing.

How much weight loss makes a difference?

For women with a higher weight who want to lose weight, losing 5 to 10% of body weight can bring real improvements in cycle regularity, ovulation, insulin and cholesterol levels, and diabetes risk ^[2]. That's 4 to 8 kg if you weigh 80 kg.

Healthy habits also improve PCOS without weight loss. Weight stigma, including in healthcare, is common for women with PCOS and can harm both health and motivation ^[1]. You don't need to lose weight to deserve good care.

What should you eat to lose weight with PCOS?

The guideline found no evidence that any one diet works better than another for PCOS ^[1]. If weight loss is your own goal and could benefit your health, what matters is a modest energy deficit in a way of eating you can keep up, ideally with support from a dietitian.

Very restrictive diets often backfire. They are linked to muscle loss, nutrient gaps, binge eating and weight regain (see how to lose fat without losing muscle). General healthy-eating evidence points to:

Vegetables, fruit, legumes and whole grains for fibre
Protein with each meal, which helps you feel full
Unsaturated fats such as olive oil, nuts and fish
Fewer sugary drinks and ultra-processed foods

Do keto, fasting or cutting out dairy help?

Keto, intermittent fasting and cutting out dairy or gluten haven't been shown to work better for PCOS. Eating disorders are more common with PCOS ^[1], so skip any approach that makes you anxious about food.

How much exercise do you need with PCOS?

The guideline recommends that adults with PCOS aim for ^[1]:

150 to 300 minutes of moderate activity, or 75 to 150 minutes of vigorous activity, a week
At least 250 minutes of moderate (or 150 of vigorous) activity a week to lose weight and keep it off
Muscle-strengthening exercise on 2 non-consecutive days a week
Less time sitting

Sleep and mental health

No single type of exercise has been shown to be best, and the same goes for the rest of your routine: what you can keep doing wins. Two things are easy to overlook.

Obstructive sleep apnoea is more common with PCOS ^[1]. If you snore or feel tired during the day, ask your doctor about it. Depression and anxiety are also more common, and getting support for them makes lasting change easier.

Do supplements or medication help?

Here's what the guideline says about the options women ask me about most ^[1]:

Inositol: considered experimental. There may be some metabolic benefit, but evidence for weight, cycles or fertility is limited.
Metformin: should be considered alongside lifestyle changes for adults with a BMI of 25 or more, to help weight and metabolic health. Prescription only.
Anti-obesity medicines, including GLP-1s: can be considered alongside lifestyle changes, following general-population guidelines. Not for use in pregnancy, so reliable contraception is needed.

Track more than the scale

Most "hormone-balancing" teas and supplement blends have no good evidence behind them. Talk to your doctor or dietitian before starting anything new.

Weight goes up and down from day to day. Your waist measurement, cycle regularity, energy, mood and blood tests (glucose, HbA1c, cholesterol) all show progress too, often before the scale does.

PCOS looks different in every body, so a personal plan works better than more general advice. At AtaHealth, I help women with PCOS find a way of eating that fits real life, without strict rules, and support you as your body and goals change. Learn more about my PCOS dietitian support.

Book your free 15-minute consultation to talk through your next step.

This article is general information, not personal medical advice. Talk to your doctor before starting medication or supplements.