Many people in the UK struggle with their weight. In fact, two thirds of adults are overweight or obese. The most common way to define healthy weight is to use the Body Mass Index (BMI = weight in kg/height in m2). A BMI over 25 kg/m2 is overweight, and a BMI of 30kg/m2 or more is classified as Obese. If you are of Asian origin lower BMI levels are used with a BMI of 27kg/m2 defining obesity. This is because people of Asian origin have a higher metabolic risk, including higher risk of developing type 2 diabetes at a lower BMI. Take this measurement with a grain of salt though. BMI neglects muscle mass - as such, you may be termed overweight when you simply are holding a lot of muscle.
Why does this matter? Well, obesity is associated with many health risks including high blood pressure, high cholesterol, heart problems, type 2 diabetes, blood clots, urinary incontinence, obstructive sleep apnoea and several types of cancer, including breast and endometrial (womb).
Obesity is not a matter of personal choice, and blaming people for being overweight is cruel and unhelpful. Around 70% of factors influencing your weight are genetic. Including genes that control appetite, whether you feel full after eating, and how and where you store body fat. A further 20% relates to the food environment. In Europe, we are surrounded by highly processed, high-sugar, high-fat foods 24 hours a day. It is common to snack rather than eat proper meals. This makes it more difficult to consciously know how much you have eaten. Unhealthy social norms of behaviour such as the super-size portions from fast food outlets and the use of high calorie energy drinks in non-athletes further challenge our weight on a daily basis.
Only around 10% of weight is down to active personal choice. This may sound depressing but in fact for most people this can make the difference between a healthy and an unhealthy weight. Understanding that you are not personally responsible for all your extra weight, and that you can make changes, will hopefully help remove the stigma around being overweight.
To be healthy at any weight you need to develop a personal healthy food environment, like a bubble of calm. We know from studies that obesity spreads through local social circles like a disease, and this pattern may be due to local micro-environments and patterns of behaviour.
Do women actually gain weight around menopause?
Both men and women tend to increase weight as they enter middle age. Some of the weight gain may be due to menopausal hormone changes, but women may overestimate these hormonal effects. This can be important as managing body weight is complex, and it is important to remember that it includes biological, psychological and social factors. It can be helpful to identify which factors are causing the problem.
Why do women gain weight around the menopause?
There is an age related decline in metabolic rate of around 10%. So you need to eat less calories to maintain a stable weight. Studies show that women often do eat less calories at this stage, but they reduce their physical activity as well so they still may end up eating more calories than they need. About 50% women gain 1.5kg a year around this time.
After the age of 50, and especially after the menopause, there is increased loss of muscle and lean body mass. Muscle burns calories. It is metabolically healthy, so as muscle drops your metabolic rate decreases, and unless you eat less calories your weight and body fat will increase.
Why do women gain inches around the middle?
This does relate to hormone changes. As the estrogen level falls and free testosterone increases, there is an increase in fat deposition around the abdominal organs, even if weight is steady. This leads to thickening around the middle waist area - also known as ‘middle aged spread’. This type of fat is associated with an increased risk of metabolic and heart problems.
Do hormones affect hunger?
The experience of hunger and the control of appetite is a complex system. It is influenced by a number of factors, including genes, personal biology, external food environment, and psychological factors. Your sex hormones do affect appetite and food consumption, as does stress.
About 70% of eating is controlled by unconscious bodily processes, with an interaction between various hormones and signals and the primitive ‘lizard brain’. Eating is also influenced by the part of our brain that is responsible for conscious thought. This is our cerebral cortex. Areas within this part of our brain respond to sensory cues, such as the sight or smell of delicious foods. People often eat for the pleasurable sensation (hedonic hunger), even when not biologically hungry. This is exploited by the advertising industry!
Psychological influences may also affect eating behaviour. Some people develop a pattern of emotional eating, using food to soothe emotional distress. This may be associated with cravings, usually for high sugar/high fat foods such as chocolate.
Sex hormones and hunger
Before the menopause, when you are having regular menstrual cycles, estrogen is dominant in the first half of the cycle before ovulation. The sex hormone estrogen is usually associated with less hunger, and reduced calorie intake. After ovulation, the hormone progesterone rises. This is associated with increased hunger, and in some women may be accompanied by cravings for particular (usually carbohydrate) foods. Progesterone is raised in pregnancy and may be associated with increased appetite and cravings during that time as well. Understanding the biology of your premenstrual chocolate cravings may be helpful, and make you feel less guilty.
In the perimenopause your sex hormones may be disrupted, leading to irregular periods, and sometimes increased appetite and cravings. Not all women experience this, but for some it is a real problem.
Also if you get unpleasant menopausal symptoms such as tiredness, hot flashes and low mood, there can be a tendency to ‘comfort eat’. Disrupted sleep is similarly associated with increased hunger, and increased food intake the next day.
So you can see that hunger is a complex process. Involving biological messages within the body, external environmental influences and sex hormones. HRT stabilises and replaces your estrogen and progesterone and therefore, may help to stabilise your weight. However, if you have put on weight during the perimenopause, you will still need to take action to lose weight. Starting HRT alone has not been proven to cause weight loss.
How do menopause symptoms impact our weight?
You may not have the energy to plan or cook healthy meals when you are feeling tired and unmotivated. You may even be tempted to comfort eat. Additionally, your physical activity may reduce, which means that you need to balance out your calories to maintain your weight.
How does stress affect hunger and weight?
The stress hormone cortisol increases hunger, and fat storage. Another stress hormone, adrenalin increases the release of energy from body stores to prepare for the ‘flight or fight’ reaction. As energy stores reduce, messages are sent to the brain to increase hunger as a way of replenishing this energy in your body.
The chemical building blocks for cortisol are the same as the building blocks for the sex hormones. So, if cortisol is high, your oestrogen and progesterone may drop. This upsets your menstrual cycle and your hunger. Some of you may have experienced your periods stopping during times of high stress, such as bereavement or exams in the past.
If you are an emotional eater or a comfort eater, you may also eat more when you are stressed. However some people report a reduced appetite and weight loss when under stress conditions.
How does HRT affect weight?
HRT does not cause weight gain! It may help change fat distribution and reduce unhealthy fat around the middle waist area. It also improves distressing symptoms, especially insomnia. This may make it easier to focus on healthy eating and increasing physical activity.
See article on maintaining a healthy weight during perimenopause/menopause for more information.
If you are interested in the fascinating science of appetite you might enjoy the book;
Why We Eat (Too Much): The New Science of Appetite
Dr Andrew Jenkinson. Penguin Life.