Why Losing Weight Isn’t Just About Willpower: Understanding Obesity
So you’d like to lose weight?
There’s a pretty universal belief that losing weight is about willpower. That if you make the right lifestyle choices and are strong-minded, the weight will fall off accordingly. But these days scientists know that it isn’t as straightforward as that. Obesity is a scenario where several factors can work against you.
What Is Obesity?
First of all, what exactly is obesity? The World Health Organisation (WHO) defines overweight and obesity as abnormal or excessive fat accumulation that presents a risk to health. A body mass index (BMI) over 25 is considered overweight, and over 30 is obese.
The number of adults classified as overweight or obese has risen steadily over the past decade, with the Health Foundation’s 2025 analysis indicating that more than 60% of UK adults now fall into this category, with around 28% who are obese.
Obesity and being overweight are high risk factors for chronic diseases such as heart disease and stroke, which are the leading causes of death worldwide. Being overweight can also lead to diabetes. Rates of diabetes have quadrupled around the world since 1980. Carrying excess weight can also lead to musculoskeletal problems including osteoarthritis. Plus obesity is also associated with some cancers, including endometrial, breast, ovarian, prostate, liver, gallbladder, kidney and colon. The risk of these diseases increases even when a person is only slightly overweight and grows more serious as the BMI climbs.1
Calculating Your BMI
You can find out your own BMI using the BMI calculator here.
The calculator asks for information on your ethnic background because people from an Asian, Black African, African-Caribbean or Middle Eastern ethnic background have a higher chance of developing health problems at a lower BMI.
Your BMI result will be displayed as a number within a category:
- Underweight
- A healthy weight
- Overweight
- Obese
Once you know your BMI and whether you are overweight or obese, you can start to make a plan for losing weight. You may want to lose weight simply to feel more comfortable about your own body, which is a very important reason. But there are multiple health reasons why you should lose weight if you are obese too. Losing just 5% of your body weight lowers your risk of diabetes and cardiovascular disease and improves metabolic function in your liver, fat and muscle tissue.
But as we’ll go onto explain, willpower is not enough to help you lose weight. It’s possible to be highly motivated, ready to move more and eat less and still struggle with weight loss. That’s because there are a myriad of reasons why a person may be obese, making it unfairly, not a level playing field. Let’s take a closer look.
A Battle Against Biology…
Professor Sadaf Farooqi, a consultant endocrinologist who treats patients with severe obesity and leads the Genetics of Obesity Study, based at Cambridge University says, “The amount of weight people gain is significantly influenced by their genes”.
For example, there’s a mutation in what’s called the MC4R gene, which means we feel less full encourages overeating. This gene mutation is carried by roughly a fifth of the global population.
There are other genes that affect metabolism – how quickly we burn energy. So that’s another factor that plays into weight gain or loss that can be affected by your genetics. We’re still learning about all of these genes.
…And The Availability of Food
Of course there are other factors. The rise in obesity can’t just be attributed to biology as biology and genetics hasn’t changed. Our changed environment plays a part too. Food is more and more available with multiple ways to purchase via home delivery services like Deliveroo, online shopping as well as shops around every corner. Ultra processed food that is more calorific is cheaper, so in a cost-of-living crisis becomes more appealing. Advertising and marketing of fast food and sugary drinks is greater than it ever was, challenging the willpower of many. Those who live in an urban environment can find it harder to exercise. This combination of factors has been called an obesogenic environment, where food marketing, food availability and urban design combine to challenge us.
How Your Appetite Changes with Weight Loss
Beyond the challenge of an obesogenic environment, your biology can conspire against you to stop you continuing to lose weight. Your body weight is governed basically by communication between the gut, fat tissue and your brain. When you cut calories, your body does a number of unhelpful things to stop you losing weight. For example if you’ve lost weight, your hunger hormone, called Ghrelin, rises before meals and stimulates your appetite.
In addition, hormones called PYY, CCK and Amylin that normally signal fullness to your brain, fall after weight loss. So meals will feel less satisfying. Plus the reward and dopamine pathways in your brain that make you feel good, are changed after weight loss, which can intensify cravings and persistent thoughts about food.
So you can see that a person who feels hungrier after losing weight is not failing; they’re just affected by their body physiology. It’s not a reason to feel guilty.
Hunger signals stay elevated for a year or more after weight loss, so maintaining weight loss is a biological challenge, not simply a motivational one.
Recommended Practice to Lose Weight
NICE, the National Institute for Health and Care Excellence, is a public body that provides guidelines to clinicians (healthcare professionals) on managing overweight and obesity. It emphasises that it’s about a whole-person approach rather than any one intervention. Important things to remember about losing weight are:-
- You should eat nutrient-dense, mostly whole foods with enough protein, which also helps preserve muscle
- Physical activity is important, with resistance training to protect lean muscle mass
- Medical treatment with evidence-based medicines, for example GLP1s, can be helpful
- Structured support from healthcare professionals, self-monitoring and a plan for maintenance of weight loss is needed
It’s helpful to think of obesity as a chronic, relapsing condition shaped by biology, environment and behaviour. Weight regain can happen because of a predictable biological response, not a lack of willpower. That’s why it’s important to set yourself up for success, by working with healthcare experts and having a plan for your weight loss goals and maintaining that loss. Don’t judge yourself or others for struggling with obesity and take advantage of all the support available to you in losing weight.
Could a GLP-1 medicine support you in your weight loss programme? You can find expert independent advice by speaking to a pharmacist at SlimEase. Call us on 01932 393965 (during standard opening hours) or click here to email the team.
