Reducing portion size - how low can we go?
By Sarah Chapman,
product development lead -
Whether it’s due to eating too much or moving too little, obesity is becoming a growing problem in the UK
. Regardless of who is responsible (the industry or the consumer), the bottom line is simple: the number
of calories the average person consumes must be reduced.
To achieve this, in 2017 Public Health England (PHE) urged manufacturers to reduce the sugar in their
products by 20% - including biscuits, cakes, sweet confectioneries and breakfast cereals - by 2020. The
following year PHE published voluntary guidelines challenging the food industry to again reduce calories
by 20% by 2024, but this time for other food categories. This included pizzas, ready meals, snack products, ready-made sandwiches and other “on the go” foods.
On the road to reduction
To help the food industry with this task, PHE suggests three ways of reducing calories. However, each
carries its own challenges:
- Reducing portion size – what’s to say consumers won’t eat two portions or reject the product?
- Encouraging consumers to purchase lower calorie products – how effective will this be?
- Changing the product’s recipe – what will the calories be replaced with?
Research into reducing portion size
Previous research has found that when we’re offered larger-sized portions, packages (e.g. big crisp
packets) or tableware (e.g. large plates), the amount of food - and therefore the calories we consume -
ultimately increases. With this in mind, reducing portion size appears to be a promising way of reducing the public’s calorie intake.
We have been looking at cake bar portions; specifically, how much we can reduce the portion size until
the consumer begins to reject the product.
The investigation, which was part of a member-funded project, presented
136 consumers with eight cake bars ranging in size from 58g down to 23g. All variables were considered to ensure the product represented, as closely
as possible, a genuine cake bar product - even down to designing mock packaging that mimicked what you would find in the supermarket. To understand
the relationship between portion size reduction and consumer acceptance of the product, we used survival analysis: a data capture and analysis
approach that, in this case, determines when a significant number of consumers begin to reject a product.
What did we find?
Overall, our research suggests that it is possible to make a 35% reduction in the size of a 58g cake bar
with the product remaining acceptable to 80% of consumers. In practical terms, this would result in a
reduction of 91 kcal and 5.9 g of sugar per bar.
What this means for the industry
Alongside the results, we also proved that using a survival analysis approach with consumer data is a
powerful way for food manufacturers to determine how much they can reduce their products’ portion sizes
before consumers begin to reject them.
Next, we will investigate the use of novel fibres and sweetness boosting natural flavours as a possible
approach toward sugar reduction.
This article first appeared in