Niki Bezzant: Downsize your plates and your waist

The researchers suggested that eliminating large portions could reduce energy intake by up to 16 per cent among UK adults. Photo / NZME.

Have you ever looked at the size of plates these days, compared to how they used to be? In the 60s, the diameter of an average dinner plate was about 25cm. Today, it's closer to 30cm. That 5cm doesn't sound like much, but research shows it is having an impact on our health.

A recent review looked at the effect of larger-sized portions, packaging and tableware on our eating habits, and concluded people consume more food or drink when offered larger-sized portions or when they use larger tableware.

The researchers suggested that eliminating large portions could reduce energy intake by up to 16 per cent among UK adults.

Much of this happens subconsciously. We don't realise we're eating more, and we still do it even when we're trying not to.

Professor Brian Wansink of Cornell University coined the term "mindless eating" to describe the ways in which we are influenced by our environment.

Some of his many findings include that we eat more of everything when we have lots of choices, as in a buffet; that we drink more from short, wide tumblers than tall, thin glasses; and we can eat up to 50 per cent more of foods with "healthy" labelling. In other words, our brains trick us into eating more than we think we are.

We're not helped by what has been termed "portion creep" -- serving sizes getting larger.

When McDonald's first opened, it served just one size of fries -- similar to today's "small". When muffins first became popular, they were baked in standard-sized muffin tins and weighed about 70g. Now a standard-sized muffin weighs more than 160g and some "healthy" sounding muffins contain the kilojoules of an entire meal.

Portion creep is partly driven by marketing: we perceive a larger serve to be better value. This is why we are susceptible to two-for-one deals or upsizing offers.

The review authors suggested that one measure that could help us might be "restricting pricing practices, whereby larger portion and package sizes cost less in relative monetary terms than smaller sizes and thus offer greater value for money to consumers."

We all know the kinds of deals they're talking about. Today at Countdown, shoppers can buy a 600ml bottle of Coke for $4.19; but a 2.25l bottle of Coke costs just $3.99.

We're also at a disadvantage when it comes to serving sizes on packaged foods and drinks.

Manufacturers are free to nominate whatever serving sizes they choose so we can be tricked by some fairly nonsensical labelling: sports drinks with four servings per bottle; corn chips with 5.7 servings per pack.

I don't know anyone who pulls out the scales to weigh 30 grams of chips. Awareness is key. Say no to bigger "value" packs unless they're something healthy.

Downsize your plates and bowls and try to eat mindfully -- step away from the phone at dinner time. We eat more when distracted by screens, so eating with focus and savouring every mouthful will help you eat less.

Size matters: comparing portions