© Matt Love & Maura Murphy


What is overweight and obesity, and how are they related to PCOS?

Most women with PCOS are affected by overweight or obesity. The two conditions seem very closely linked, since any increase in weight makes it more likely to have PCOS, and women with PCOS tend to gain more weight over time. Often, weight gain in PCOS starts around the time of the first periods and continues throughout life.

Women with PCOS who have overweight or obesity have a higher risk for developing health conditions such as diabetes compared with women of the same body weight and fat mass but without PCOS. In addition, many women with PCOS find that their PCOS symptoms worsen as their body weight goes up. Because of all this, it is important to address excess weight as part of the treatment for PCOS. Losing weight not only lowers the risk of future health problems, it may also improve the symptoms of PCOS.

It is well known that overweight and obesity increase the likelihood of developing health problems such as:

  • type 2 diabetes
  • fatty liver
  • heart disease
  • strokes
  • obstructive sleep apnoea
  • arthritis

How do I know if I have obesity?

To find out whether you have overweight or obesity, you will need to calculate your body mass index (BMI). For this you need to know your height and weight. There are many online calculators and apps that can help you calculate your BMI easily, for example on the NHS website: www.nhs.uk/live-well/healthy-weight.

Depending on the BMI, a person will be in one of the following groups:

Note that if your ethnic background is other than White Caucasian, the BMI cut offs might be different from the above, e.g. for Black and Asian a BMI of 23.0 or more is considered overweight, and a BMI of 27.5 or more obesity.

What can be done about having overweight or obesity?

If you have overweight or obesity you should talk to your healthcare team to discuss the different options available to help you lose weight. Even small changes in your weight, e.g. managing to lose 5-10% of the initial body weight, can have significant positive effects on health and PCOS symptoms. Your healthcare team will discuss your individual needs and agree with you the best approach to losing weight. As people are different, there is no approach to weight loss that works for everyone. A plan for each patient should be drawn up, supported by a team consisting of doctors, dietitians, and psychologists. The good news is that women with PCOS who achieve weight loss can see significant improvements in insulin resistance, androgen levels, fertility and overall cardiovascular risk.

What options for weight loss are available?

Dietary and exercise interventions:

The most important step is living a healthy lifestyle by developing healthy habits around eating and exercise. In contrast to what you may find on the Internet, there is no such thing as a “PCOS diet”. A healthy, balanced diet with appropriate meal portion sizes should be followed, and eating behaviours that result in weight gain, e.g. snacking out of boredom or because of low mood, should be avoided. The exact type of diet should be agreed with a dietitian or other member of your healthcare team. Depending on the individual situation, support from a psychologist might be required.

A good starting point is the HSE Healthy Eating guideline, which provides lots of free advice, including a diet plan (https://www.hse.ie/eng/about/who/healthwellbeing/our-priority-programmes/heal/healthy-eating-guidelines/).  If you have a smartphone, you can also use one of the many health tracking apps available. They can help you monitor your weight, identify foods in your everyday diet that contain a lot of calories, help you reduce portion sizes, and track your activity. You could also consider joining one of the commercial weight loss groups, such as Weight Watchers. Beware that there is a cost implication and that these are group sessions where talking in front of other people about weight issues might not suit everybody.

Exercise is an important part of a healthy lifestyle. The benefits of exercise are not necessarily related to weight loss, but to the protection it provides from future health problems by increasing your fitness. While joining the gym might be the first thing you would consider, it might be better to start simpler by increasing the amount of walking. For example, you could get off the bus one stop sooner, park further away from your home or working place, take the stairs and not the lift or escalator, or use the bicycle instead of the car. There are several apps that can track your exercise or daily steps, and they can help increasing your physical activity especially if you are not very active at all at present. You can find more information about exercise on the HSE exercise guidance portal (https://www2.hse.ie/healthy-eating-active-living/exercise) .

In general, for weight loss for adult women 300+ mins/week of moderate activity or 150+ mins/week of vigorous activity or a combination of both is required. Try to include weight training twice weekly.  However, any physical activity is likely to be beneficial.

Weight loss medications:

The only weight loss medication available in Ireland for women with PCOS is called Orlistat. It is a tablet that prevents fat in the diet from being taken up from the gut, thus reducing the amount of calories taken up from the food. It should only be used in combination with a balanced healthy diet, and there are weight targets that have to be achieved in order to be able to stay on it. Orlistat should only be taken after consultation with your healthcare team. If you have diabetes, there are some further options, but the majority of women with PCOS who are young do not have diabetes. Metformin may also be offered, and whilst there are some clear benefits from this medication for women with PCOS such as an increase in ovulation, the weight loss benefits are only modest.

Bariatric Surgery:

Bariatric surgery might be the only realistic option in people who have a severe degree of obesity. It is very effective in terms of weight loss than can be achieved, but as with any type of surgery there is a risk of complications. Bariatric surgery should only be accessed through a designated Weight Management Clinic, and your healthcare team will advise you if necessary.

Due to the likelihood of rapid return of fertility post surgery patients need to commit to effective contraception, ideally prior to surgery.  Contraception should be continued until a stable weight is achieved, usually after one year, to avoid complications.

Referral to a Weight Management clinic

Some services have links to sWeight Management clinics. If your BMI is above 40kg/m2, or above 35kg/m2 with complications such as subfertility, you may be referred to one of these clinic depending on local services The potential interventions offered will be individualised, depending on the degree of obesity, your age and other factors such as plans to conceive

This information leaflet has been co-authored by:
Dr. Michael O’Reilly (Consultant Endocrinologist, Beaumont Hospital)
Professor Francis Finucane (Consultant Endocrinologist and Weight Management specialist, Galway University Hospitals)
Ms. Maureen Busby (CEO and Founder, PCOS Vitality patient support group https://www.pcosvitality.com/what-is-pcos)

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