Obesity: watch those portions

Even small, often hard to detect, increases in food portion sizes can lead to obesity problems, a food industry conference has heard.

Eating one extra biscuit or choosing a larger size pizza on a regular basis gives you higher odds of moving from a normal weight into obesity, Dr Sinéad McCarthy of Trinity College Dublin told a Food and Drink Industry Ireland conference yesterday.

"Eating a little bit more food, or just eating a few more grammes per day, can have a big effect. Taking in 157 calories requires 45 minutes of sit-ups to burn off," Dr McCarthy said.

Eating just 271 extra calories a day can make the difference between being a normal weight and being obese, she said.

Many consumers might not notice that they are consuming extra food, particularly if they are not preparing it.

"Average portion sizes are becoming increasingly dissociated from standard serving sizes. When food is presented as a unit, people will eat it as a unit. They are consuming more energy without really realising it."

Consumers can easily double the amount of calories in a meal by increases in the portion sizes of particular components of a meal.

A lunch that includes 250ml soft drink, a 25g bag of crisps, a sandwich with two slices of bread, 14g of butter and 25g of cooked meat and a snack-sized bar is 702 calories.

A similar meal with a 500ml drink, 40g crisps, a club sandwich with three slices of bread, 21g of butter and 50g of cooked meet and a king-size bar increases to 1,294 calories.