Forget slow and steady, new research suggests that body fat is gained in sudden surges after disruptions like holidays, injury, or life changes, prompting a call to rethink how we prevent obesity.
Perspective: Lifestyle instability: an overlooked cause of population obesity? Image Credit: VIGO-S / Shutterstock
In a recent perspective article published in the International Journal of Obesity, researchers drew attention to the possible role of lifestyle disruptions in driving fat gain and discussed what is needed to prevent and effectively intervene in these cases.
Global burden of obesity
In 2022, the World Health Organization estimated that one in eight people in the world were living with obesity. Statistics suggest that since 1990, obesity among adults has more than doubled, while among adolescents, it has quadrupled.
Public health researchers consider obesity to be a worldwide epidemic, with significant health and economic costs. It is a pressing global public health issue, and numerous avenues are being explored to reduce its prevalence and manage the condition, as well as its associated health complications.
There are promising indications that obesity rates in adults may be stabilizing, mainly in high-income countries. However, childhood obesity continues to rise, and concerningly, the prevalence of severe obesity is increasing. While pharmacotherapeutic advancements have led to improved management of obesity for those who can access them, public health strategies are lagging.
Prevention is better than a cure
Obesity is known to increase the risk of heart disease, type 2 diabetes, and certain cancers. It can affect reproduction, bone health, and quality of life, including actions such as moving and sleeping. Public health researchers have noted that preventing obesity will result in greater economic and health benefits than treating it.
With these factors in mind, efforts have focused on addressing the root causes of body fat gains. Obesity and overweight result when imbalances occur between energy intake from the diet and energy expenditure through physical activity. However, obesity is, in most cases, a multifactorial disease that results from genetic and psychosocial factors and obesogenic environments.
However, from this perspective, researchers drew attention to the misunderstanding of fat gain dynamics, particularly the assumption of gradual and continuous accumulation, while recognizing the importance of economic, political, and socio-economic influences. Their argument focuses on the need to rethink fat gain models to address this pressing issue.
Rethinking body fat gain models
The common assumption is often that fat gains occur gradually through small but sustained daily surpluses. However, emerging evidence indicates that, on the contrary, the major driver is large but short-term episodes when the energy balance is positive, often triggered by disruptions to daily life that create temporary mismatches between expenditure and intake of energy.
The authors refer to these episodic disruptions as ‘lifestyle instability’ and argue that it can cause significant, if temporary, energy imbalance. Rather than continuous and slow accumulation, such disruptions could lead to intermittent, stepwise fat gains that are not fully reversed. Thus, rather than reflecting a constant surplus of energy, fat gain may represent an inability to fully recover from these episodic gains.
Traditionally, models of fat gain have been based on infrequent measurements, such as annual weigh-ins during doctor’s visits. Some calculations suggest that daily energy imbalances could be as low as 12kcal per day, the equivalent of a handful of grapes. This narrative overemphasizes the role of small daily habits while underestimating the contribution of acute, lifestyle-induced disruptions.
With new technology, it is becoming possible to track changes in body composition and mass more frequently, often daily. The findings show that body mass is significantly variable in the short term, with seasonal fluctuations and spikes during holidays such as Christmas. In the United Kingdom, for example, intakes during the festive season rise to 6000kcal per day, similar to what cyclists in the Tour de France consume!
Other than holidays, parenthood, injuries, illness, medication use, career changes, relationships, and living situations can lead to gains in body fat. The authors refer to the well-known phenomenon of the Freshman 15 – the three to four kg in weight gain often seen by students when they start university.
Implications for preventing obesity
Targeted awareness is critical to ensure that individuals recognize the importance of high-risk periods for fat gain. Better support systems, including education and tools, must be put in place to help people manage energy balance during these periods. Rather than focusing solely on everyday habits, prevention efforts should target these disruptive events.
The authors note the role that technology can play in supporting self-management. Commercial tools are already available that allow individuals to monitor movement and track diets. In the future, artificial intelligence (AI) could power personalized coaching while machine learning algorithms could help recognize behavioral patterns. The effectiveness of these interventions depends on their accessibility, as well as user interest and engagement.
Conclusions
Further research is needed to understand how fat levels vary around important life events and the extent to which gains are reversed after the disruption. This requires the development of large datasets that track activity, dietary behaviors, and daily body composition. These efforts should prioritize vulnerable populations and elucidate the mechanisms that underlie lifestyle-induced gains.
Some implications also emerge for public health efforts. If lifestyle disruptions are truly the primary contributors to fat gain, then prevention strategies must target these events to be effective. Episodic fat gains may be best addressed through event-specific and short-term rather than sustained support.