Many people want to know what their healthy weight is. Unfortunately, common tools like the body mass index (BMI) teach us that everyone should fall into a narrow weight range to be considered healthy.
The BMI is a highly inaccurate tool that misses out a lot of information when it comes to health. Rather than using BMI to determine your healthy weight, I invite you to consider something called your set-point weight.
A set-point weight is not one number but a weight range that your body is programmed to maintain. Within this weight range, your body feels comfortable and safe. When you begin to stray to far away from this set point range, your body kicks into action to help you return to your safe and comfortable weight. Your body’s determination to maintain your set-point weight is what makes it so challenging to sustain long-term weight loss.
A landmark 1995 study showed how our body reacts to weight gain and loss. The study looked at the metabolic rate of 18 “obese” and 23 “never obese” participants. The participants were kept in a controlled environment for up to 2 years while their metabolic rate was measured at different body weights.
Participants were fed liquid diets to either help them gain 10% of their body weight or lose 10-20% of their body weight. Researchers found that when participants’ weight moved beyond their set-point range, their metabolism altered in order to bring their weight back to its safe range. For example, when participants lost weight their metabolism slowed down in order to burn less energy and return them to their usual weight.
It is not only our metabolism that responds to weight changes, our hormones also play a role. Hormones control our hunger and appetite by providing messages to our brain regarding our energy stores (fat and glycogen). When our energy stores are low, our hunger hormones increase and encourage us to eat. When our energy needs are met, fullness hormones increase indicating we can stop eating. If you fall below your set-point weight, your hormones levels will change in effort to get you to eat more food and gain weight.
Put simply, your body fights to defend its happy weight range by changing your metabolism and hormones.
Research shows that 70% of your weight is determined by your unique genetic makeup. That is huge! Your body size is decided by something that is completely out of your control. Environmental factors like food intake, physical activity, stress levels, and income also play a role in determining body size but the vast majority is in your DNA.
The diet industry wants us to believe that we are in control of our weight. They encourage us to buy their detox programs, calorie counting apps, join weight loss support groups, and take medication. We are promised a smaller body if we eat less and move more. But if this were true, all the hard work and commitment you have put towards weight loss would have paid off. Intentional weight loss does not work for the vast majority of people and is likely making you sicker rather than healthier.
Every time you embark on a weight loss journey you are dropping below your safe and comfortable weight range. Your body gets to work by slowing your metabolism and changing your hormones. It is resisting weight loss until you return to your set-point weight range.
This does not mean your body weight will never change. Our body changes all the time due to life stages, ageing, stress or illness. It just means that we do not have control over our body weight like we have been told. It is impossible to predict how your weight will change throughout your life.
It is important not to treat your set-point weight like a diet. This is not a new weight goal that you must achieve and maintain. Finding your set-point weight is not about numbers, it is about nourishing your body with adequate nutrition and allowing your weight to settle in a place where your body can perform its best. This does not mean it won’t be challenging. Letting go of a perceived sense of control that comes with weight loss goals and dieting is hard. But your body is smart, and it has so many intricate processes in place to look after you.
Determining your set-point requires you to consistently nourish your body. You may need to address some eating behaviours and thoughts that are stopping you from eating enough food. Whether it is being trapped in the binge-restrict cycle or feeling the pressure to be thin from doctors or loved ones. There are many ways we are discouraged from nourishing our body. Addressing these beliefs that we have been taught about food and our bodies is vital to develop a healthy relationship with food and to accept and appreciate our body.
If you want to let go of the restrictive diet rules and unhelpful weight loss goals, Kim is a dietitian who provides gentle nutrition counselling through a virtual clinic Australia wide. Kim takes an approach that is personalised to each individual and seeks to understand what you need to reach your health goals. Kim is a Credentialed Eating Disorder Clinician and has a special interest in digestive health and chronic dieting. Find out more here.