Reducing obesity, particularly in children, has been a major aim of governments for many years. It is likely that lockdown in response to the pandemic has been having the opposite effect – making daily life more sedentary, reducing physical activity and increasing food consumption.
Obesity was a major public health problem in the UK before Covid-19 hit; and obese people are likely to be hit harder by Covid-19 (Garg et al, 2020).
Obesity results from a person consuming more calories than they burn in physical activity. Anecdotal evidence indicates that lockdown has led to more sedentary behaviour, decreased physical activity and increased food consumption, all of which suggests that obesity will rise, leading to more long-term health problems.
What does evidence from research tell us?
Obesity is a major health problem around the world, and particularly in the UK (OECD, 2017). Obesity is associated with many diseases and is a leading risk factor for premature death. Our World in Data provides clear and comprehensive information on some of the key facts and figures about obesity. Reducing obesity, particularly in children, has been a major aim of government for many years (Childhood obesity: a plan for action).
Research has linked obesity to sedentary behaviour. A US study finds that watching more TV is associated with obesity and weight gain, independent of diet and exercise (Hu et al, 2017). This is not a causal effect: people who watch more TV are also more likely to engage in other activities that are associated with obesity and weight gain, such as eating more snacks and processed foods and fewer vegetables and fresh foods.
A large part of the calories that people burn is from daily activities, such as commuting and moving around (Griffith et al, 2016). Daily life has become more sedentary with lockdown, which means that it is very possible that we will see a rise in obesity. In addition, for some people, stress and loneliness may lead to increased calorie consumption and snacking.
Anecdotal evidence suggests that lockdown has increased sedentary behaviour (for example, screen time) and decreased physical activity (Winther and Byrne, 2020). Overall it seems likely that sedentary activity has increased, although the evidence is not entirely clear, and it seems likely that as with many other effects of this crisis, the effects will be felt unequally. For example, one study shows that people in France and Switzerland had changed their levels and types of physical activity (Cheval et al, 2020).
A recent study in Verona, Italy, finds that lockdown has led to a decrease in sports activity by 2.3 hours per week on average in a sample of 41 children aged 6-18 years (Pietrobelli et al, 2020), and an increase of 0.65 hours of sleep per day. Screen time has increased by an average of 4.85 hours per day, and the number of meals eaten per day by an average of 1.15.
Lockdown in Italy was stricter than in the UK, with people not being allowed outdoors. In the UK, the NHS has reported that downloads of its ‘Couch to 5k’ app have increased (BBC, 1 July 2020); but time spent playing games on mobile phones has also increased dramatically (Financial Times, 30 June 2020)
A survey commissioned by Obesity Action Scotland reveals that around one in five people are eating more family meals, almost half are eating takeaway food less often, around one in four are eating fewer ready-made meals, and nearly one in three are eating more fruits and vegetables.
But there is also evidence of increased unhealthy behaviour, with over half of people saying that they are eating more because they are bored, eating more cakes, eating more confectionary and one in three drinking more alcohol. More than one in three say that their physical activity levels have worsened and similar numbers say that their diet has worsened; overall, two in three people are worried about their body weight.
A large number of studies suggest that obesity is associated with a person's physical, economic and social environment. For example, being discriminated against due to weight adversely affects weight-related behaviour such as the consumption of high calorie foods and physical activity (Jackson and Steptoe, 2017).
The way that food is presented and the environment in which it is eaten can affect the amount consumed – for example, the size of the plate (with larger plates being associated with more consumption); and whether people are only eating or also engaged in other activities such as watching TV (with more food being consumed if people are also engaged in other activities).
Regular family meals lead to healthier eating patterns later in life, such as higher ‘intakes of fruit, vegetables, calcium-rich foods, protein, fibre’ and less consumption of ‘soft drinks, fried food and saturated fat’ (Larson and Storey, 2009).
Other research suggests that this effect varies, for example, with overweight children consuming more calories while watching TV alone than when in a group and listening to music (Marsh et al, 2013), an effect not seen in normal weight individuals. This suggests that the effect of sedentary behaviour, such as watching TV, on calorie consumption may be amplified for people who are already overweight and who are spending more time alone during lockdown.
Most of the evidence on the drivers of obesity establishes associations with individual behaviour or characteristics, but does not necessarily establish a causal relationship. Is it watching more TV that leads to a more sedentary lifestyle and weight gain; or do people who are more sedentary for other reasons also watch more TV and gain weight? The research is often unable to answer that question clearly.
What might be effective policy responses?
Before the pandemic, the government was actively considering many policies that aimed to reduce obesity. For example, the sugar reduction plan (Public Health England, 2019) led to the Soft Drinks Industry Levy. Many other policies were under consideration, including restrictions on advertising to children (Griffith et al, 2020; and Tan et al, 2020).
Lockdown has created two main risks for children: the food environment and reduced physical activity. We are already seeing some innovative approaches to addressing food insecurity, including the UK government’s COVID Summer Food Fund. A remaining challenge for schools is how to deliver physical education in an online learning environment (Rundle et al, 2020).
What research is under way?
The Economic and Social Research Council has funded a project on The impact of the COVID-19 crisis on nutrition, led by Martin O’Connell at the Institute for Fiscal Studies: ‘A major challenge facing policy-making during the COVID-19 crisis is ensuring all households have access to a nutritious diet. … Many households are under significant financial pressure, some low-income families have lost access to free school meals, and interrupted supply chains and hoarding by some consumers are leading to significant upward pressure on food prices. We will provide evidence on whether vulnerable people – e.g. the elderly, those on low incomes, and those with young children – are having difficulties accessing essentials and maintaining a healthy diet.’
The Association for the Study of Obesity is conducting a study of the impact of Covid-19 on individuals with obesity.
Adrian Brown at University College London has two research projects on obesity and Covid-19: a on survey on the impact of Covid-19 on weight management & bariatric services in the UK; and a survey studying the impact of Covid-19 on people living with obesity in the UK.
Nicholas Sculthorpe at the University of the West of Scotland is investigating the impact of lockdown on mental and physical health.
Where can I find out more?
In Gluttony and Sloth, Rachel Griffith and Melanie Luhrmann discuss trends in calories and the strenuousness of work and daily life in the UK.
Susan Jebb discusses what types of interventions might lead to better diet and nutrition, and a reduction in obesity in her Academy of Medical Sciences lecture.