Understanding Weight Management: Beyond Individual Willpower

Public discourse regarding obesity often attributes weight management solely to individual willpower. A study published in The Lancet, involving participants from the UK, Australia, New Zealand, and the US, indicated that 80% of respondents believed obesity could be entirely prevented by lifestyle choices alone. However, some medical professionals and experts present a more complex view.

Bini Suresh, a dietitian with 20 years of experience with obese and overweight patients, states that many highly motivated individuals consistently struggle with weight. Dr. Kim Boyd, medical director at WeightWatchers, asserts that terms like "willpower" and "self-control" are insufficient, noting that obesity is a complex condition. Experts suggest various contributing factors to obesity, some of which are not yet fully understood, indicating an unequal playing field for individuals.

Government Interventions and Public Health

The UK government has implemented regulatory measures to address obesity. A ban on junk food advertising on television before 9 pm and a complete prohibition on online promotions for these products took effect recently. Despite these measures, some observers believe their impact on the UK's obesity problem, affecting over one in four adults, may be limited.

Biological and Genetic Influences

Professor Sadaf Farooqi, a consultant endocrinologist at Cambridge University who leads the Genetics of Obesity Study, explains that an individual's genes significantly influence weight gain. These genes affect brain pathways regulating hunger and satiety in response to signals from the stomach. Variants in these genes can lead to increased hunger and reduced feelings of fullness after eating.

• The MC4R gene is identified as a key gene, with a mutation found in approximately one-fifth of the global population, which is associated with overeating and reduced satiety.
• Other genes influence metabolism, impacting how quickly energy is burned. This means some individuals may gain more weight or store more fat from the same food intake, or burn fewer calories during exercise, compared to others.
• Prof. Farooqi estimates that thousands of genes influence weight, though only about 30 to 40 are understood in detail. She highlights the significance of new weight-loss drugs in combating these biological factors.

The Set Weight Point Theory and Yo-Yo Dieting

Andrew Jenkinson, a bariatric surgeon and author, describes the "set weight point theory," which posits that the brain maintains a preferred weight range for an individual. This set point is determined by genetics and environmental factors such as food, stress, and sleep. The body functions like a thermostat; if weight drops below this set point, hunger increases, and metabolism slows to restore the preferred weight.

This theory can explain the phenomenon of yo-yo dieting. When an individual loses significant weight below their set point, the body's reaction can be similar to starvation, leading to increased appetite, food-seeking behavior, and a lowered metabolism. These appetite signals are described as profoundly strong and difficult to ignore.

Dr. Jenkinson further explains the role of leptin, a hormone produced by fat cells, which signals to the hypothalamus (the brain region controlling the weight set point) about the body's energy storage. Ideally, high leptin levels would decrease appetite and increase metabolism. However, in the Western food environment, high insulin levels can dilute the leptin signal, impairing the brain's ability to sense fat storage. The set point is not entirely fixed; it can gradually shift through sustained lifestyle changes, improved sleep, stress reduction, and long-term healthy habits.

The Obesogenic Environment in the UK

Despite biological factors, genetic makeup has not changed over recent decades, suggesting other influences on rising obesity rates. The proportion of UK adults classified as overweight or obese has steadily increased, with over 60% falling into this category and approximately 28% being obese, according to the Health Foundation's 2025 analysis.

This trend is attributed to several factors:

• The high volume and affordability of poor-quality, high-calorie, and ultra-processed foods.
• Aggressive marketing and advertising of fast food and sugary drinks.
• Increasing portion sizes.
• Limited opportunities for physical activity, often due to urban design or time constraints.

Prof. Farooqi notes that this environment has led to a population-wide increase in obesity, particularly affecting those with a genetic predisposition to weight gain. Public health experts refer to this as the "obesogenic environment," a term coined in the 1990s, linking rising obesity to external factors like food availability, marketing, and urban design. These factors are argued by many experts to create persistent cues toward overeating and inactivity, posing challenges for individuals aiming to maintain a healthy weight.

The Debate on Personal Responsibility and Public Health Policy

Alice Wiseman, public health director for Newcastle City Council and Gateshead, observes the prevalence of food establishments in urban areas, suggesting visibility influences food choices. Gateshead has not granted planning permission for new hot food takeaways since 2015. However, the UK fast-food and takeaway industry is valued at over £23 billion annually, and food advertising is dominated by products high in fat, salt, and sugar.

Ms. Wiseman, also Vice President of the Association of Directors of Public Health, suggests that current measures to restrict junk food advertising may have limited impact. A report by The Food Foundation indicated that healthier foods are more than twice as expensive per calorie than less healthy alternatives, presenting challenges for low-income families. While acknowledging the role of personal responsibility, Ms. Wiseman questions why willpower would have diminished across the population, stating, "We're living in an environment engineered for over-consumption." She concludes that "Obesity is not a failure of character. It's a complex, chronic condition shaped by biology and a highly obesogenic environment. Willpower alone is not enough and framing weight loss as solely a matter of discipline does harm."

Conversely, Professor Keith Frayn, author of A Calorie is a Calorie, agrees that the environment, not willpower, has changed over 40 years. However, he expresses concern that dismissing willpower might encourage resignation to an unhealthy weight. He references the National Weight Control Registry in the USA, where over 10,000 participants who successfully maintained weight loss describe the process as "hard," suggesting that they would be "affronted" by the idea that willpower plays no role.

State Intervention and Individual Choice

The discussion also encompasses the extent of state responsibility. Ms. Wiseman advocates for regulation, such as restricting buy-one-get-one-free deals, as an important tool. In contrast, Gareth Lyon, head of health and social care at Policy Exchange, argues against further legislation, stating that bans and taxes make life "harder, less enjoyable and more expensive." Christopher Snowdon, head of lifestyle economics at the Institute of Economic Affairs, views obesity as an "individual problem" stemming from individual choices, questioning the government's role in making people slimmer and advocating for independent evaluation of policies.

The Nuance of Willpower

Experts generally agree that willpower plays some role, though its extent is debated. Ms. Suresh views it as one component within a broader framework. She emphasizes that educating individuals about biological factors can shift the focus from moral judgment to a "compassionate, science-informed support system," potentially leading to better long-term success.

Dr. Eleanor Bryant, a psychologist at Bradford University, notes that willpower is not constant; it is affected by mood, fatigue, and hunger. She distinguishes between "flexible" and "rigid" willpower:

• Rigid willpower: An all-or-nothing approach, where succumbing to temptation (e.g., eating one biscuit) leads to abandoning the goal entirely ("disinhibited eating").
• Flexible willpower: A more adaptive approach, where one can acknowledge a lapse (e.g., eating one biscuit) but stop there.

Dr. Bryant states that flexible willpower is more successful, but exercising willpower with food is particularly challenging. Ms. Suresh adds that understanding the biological limits of willpower can actually strengthen an individual's ability to exercise it, especially when combined with structured nutrition, consistent meal patterns, psychological strategies, and realistic goals, leading to improved relationships with food.