̽��ֱ�� of Cambridge - James Reynolds

No evidence that physical activity calorie-equivalent labelling changes food purchasing – study

cjb250 — Wed, 09 Nov 2022 08:30:30 +0000

More than three in five UK adults are overweight or obese, increasing their risk of diseases such as type 2 diabetes and cancer. A major factor that contributes to this is excess energy intake – in other words, eating too many calories. Measures that can help reduce energy intake could help tackle the obesity problem.

In the UK, adults eat as many as a third of their meals out of home, including in workplace cafeterias, and these meals are often much higher in calories than meals eaten at home. Since April 2022 calorie labelling is now required on food and drink served out of the home in businesses employing 250 or more people. While many people welcome this information, evidence for its effectiveness in reducing calories purchased or consumed is limited in quantity and quality. For example, two previous studies conducted by the authors in nine worksite cafeterias found no evidence for an effect of simple calorie labelling (kcal) on calories purchased.

Another option is to show the amount of exercise required to burn off these calories – so-called PACE (physical activity calorie-equivalent) labels – for example, a 1014kcal ‘large battered haddock’ portion would take upwards of five hours walking (278 minutes) to burn off. A recent systematic review – a type of study that brings together existing evidence – concluded that PACE labels may reduce energy selected from menus and decrease the energy consumed when compared with simple calorie labels or no labels, but only one of the 15 studies reviewed was in a ‘real world’ setting.

To explore whether PACE levels can make a difference in real world settings, researchers from the ̽��ֱ�� of Cambridge’s Behaviour and Health Research Unit carried out an experiment across 10 workplace cafeterias in England over a 12 week period in 2021. Their results are published today in PLOS Medicine.

̽��ֱ��team collected baseline sales data for a period of business-as-usual for the cafeterias ahead of the experiment. During this period, most labels and menus featured only the product name and price, though some products included standardised front-of-pack nutrition labels on branded and in-house products. During the intervention period the ten cafeterias included calorie information and PACE labels alongside food and drinks items and on items including hot meals, sandwiches, cold drinks and desserts. These labels displayed the minutes of walking that would be needed to burn off the calories in the product.

̽��ֱ��team found no evidence that including PACE labels resulted in an overall change in energy purchased from labelled items. However, there was a great deal of variability, with one cafeteria reporting a fall per transaction of 161kcal and another an increase of 69kcal, while five of the cafeterias reported no significant change.

First author Dr James Reynolds from the School of Psychology, Aston ̽��ֱ��, who carried out the research while at Cambridge, said: “Although we found that showing the amount of exercise required to burn off calories made little difference to the number of calories purchased – and, we can assume, eaten and drunk – there was considerable variability between cafeterias. This suggests that other factors may have influenced the effectiveness of these labels, such as the type of food sold in the cafeteria or the characteristics of those using them.”

̽��ֱ��number of calories purchased from items that did not feature the PACE labels did not change and the labels made little difference to the revenue for the cafeterias – just a small increase of 3p per transaction.

Senior author Professor Dame Theresa Marteau, Director of the Behaviour and Health Research Unit and Bye-Fellow of Christ’s College, ̽��ֱ�� of Cambridge, said: “This is the largest study in a real world setting to look at the impact of PACE labels on food and drink purchases, examining 250,000 transactions across 10 worksite cafeterias. ̽��ֱ��findings suggest that PACE labels, contrary to expectations, may have little or no impact on the food people buy in worksite cafeterias.”

Reference
Reynolds, JP et al. Evaluation of physical activity calorie equivalent (PACE) labels’ impact on energy purchased in cafeterias: a stepped-wedge randomised controlled trial. PLOS Med; 8 Nov 2022; DOI: 10.1371/journal.pmed.1004116

An experiment carried out across ten workplace cafeterias found no significant change in the overall number of calories purchased when food and drink labels showed the amount of physical activity required to burn off their calories.

̽��ֱ��findings suggest that physical activity calorie-equivalent labels, contrary to expectations, may have little or no impact on the food people buy in worksite cafeterias

Theresa Marteau

̽��ֱ�� of Cambridge

PACE labels alongside menus

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Changes to workplace cafeteria menus nudge workers to consume fewer calories

cjb250 — Tue, 14 Sep 2021 18:00:39 +0000

Researchers at the ̽��ֱ�� of Cambridge, who led the study, say that even simple interventions such as these could contribute towards tackling levels of obesity.

Unhealthy eating, including eating more calories than are needed, plays a major role in the increasing rates of obesity. This in turn increases the risk of diseases such as type 2 diabetes, heart disease and many cancers, contributing to increasing rates of premature death worldwide.

̽��ֱ��environments in which we live and work influence the types of food and drink that we consume. Local areas of deprivation in particular magnify this effect – people living in less affluent areas or with lower socioeconomic status tend to have reduced access to healthy foods and higher rates of obesity.

One important environment where interventions could be implemented is cafeterias, such as those in schools, universities, and workplaces. ̽��ֱ��workplace is the most common place to eat outside of the home, typically 15% of working adults’ energy intake.

In the largest study of its kind, a team from the ̽��ֱ�� of Cambridge tested the impact on calories purchased of changing both portion sizes and availability of some higher calorie food and drink in 19 workplace cafeterias over a six month period. ̽��ֱ��results of their study are published today in PLOS Medicine.

̽��ֱ��team recruited workplace cafeterias based in the distribution centres of a major UK supermarket chain.

Over a 25-week-long period, the team, working with the caterers, replaced some higher calorie food and drink products with lower calorie ones – for example, swapping bacon and cheese burgers with grilled chicken burgers. This led to a 4.8% reduction in the average number of calories purchased a day.

Next, as well as reducing the availability of high calorie food and drink products, the team reduced the portion size of some higher calorie products by about 14% in volume – for example by serving a smaller slice of lasagne or portion of chips or reducing the number of meatballs in a portion.

When both the availability and size of high calorie food and drink portions were changed, this led to an 11.5% reduction in the average number of calories purchased per day compared to the baseline. For the typical worker, this would be equal to eating about 50kcal fewer per day.

Dr James Reynolds from the Behaviour and Health Research Unit at the ̽��ֱ�� of Cambridge, the study’s first author, said: “On average, UK adults consume 200-300 excess calories a day. This study shows that reducing portion sizes and the availability of higher calorie options in cafeterias could make an important contribution to reducing excess calories in strategies to tackle obesity.

“If cafeterias in workplaces, schools, and universities implemented these changes, this could help reduce overconsumption of calories and help in widespread efforts to reduce population-level obesity.”

̽��ֱ��workplaces where the cafeterias were located were predominantly staffed by those working in manual occupations, who have – on average – worse health outcomes and higher body mass indexes (BMIs) compared to those in non-manual occupations.

Senior author Professor Dame Theresa Marteau, Director of the Behaviour and Health Research Unit, added: “Many of the measures introduced to reduce calorie consumption, such as mass media campaigns, have little overall impact, but can exacerbate health inequalities, helping mainly those who work in non-manual jobs. We need to find interventions that works across the board. Our study suggests that making relatively simple changes to menus in workplace and other cafeterias could make an important contribution to tackling obesity in all groups.”

̽��ֱ��study took place over a longer time period and used more sites than previous studies. Sustained behaviour change is known to be a major obstacle to reducing body mass index (BMI), but the researchers found no evidence that the effect of the intervention diminished with time during their study.

̽��ֱ��cafeterias experienced a small drop in the amount of money taken at the till – 2.6% when just the availability of options was reduced and a 5.7% drop when the portion sizes were also decreased. ̽��ֱ��researchers suggest this may have been a temporary effect, as the drop decreased over time, and may in part be due to the fixed menu and product list that was required for the study.

Dr Reynolds added: “Cafeterias should be able to compensate for a small drop in revenue by changing which products they sell or by additional strategies to make healthier food options more appealing.”

̽��ֱ��study was funded by Wellcome Trust and Cancer Research UK.

Reference
Reynolds, JP et al. Impact of decreasing the proportion of higher energy foods and reducing portion sizes on food purchased in worksite cafeterias: a stepped-wedge randomised controlled trial. PLOS Medicine; 14 Sept 2021; DOI: 10.1371/journal.pmed.1003743

A study carried out at 19 workplace cafeterias has shown that reducing portion sizes and replacing higher calorie food and drinks with lower calorie options led to workers buying food and drink with fewer calories.

Our study suggests that making relatively simple changes to menus in workplace and other cafeterias could make an important contribution to tackling obesity

Theresa Marteau

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