Oliver Conway

So people who are smaller, generally women more than men, people from less affluent versus more affluent are shorter.

Therefore, they need less energy for their body's requirements.

And if we offer single portion sizes, which are really to fulfill the requirements of average men, we're nudging gradually and progressively nudging more and more people to eat more than they need.

And that is contributing to widening obesity disparities.

Clearly, costs should be proportioned to the volume of food.

I mean, if you're getting 75%, I suppose the cost should be 75% of the 100% cost.

So the issue, of course, then means that places that make food or make various products, probably their profit margin might be somewhat less.

But actually, the reality is there's far too much food all over the place.

Food companies, drinks companies are making huge amounts of profit.

Perhaps they need to make slightly less profit to make healthier versions, both by portion or by composition.

And that's the direction of travel we need to go in if we're going to seriously tackle the obesity pandemic.

I mean, I'm not saying that's the only solutions.

Clearly, the sugar tax is helping, but certainly portion sizes.

You know, when I was sitting with my wife and she got a huge portion of breakfast cereal porridge, actually, and she felt guilty not being able to eat even half of it and over-consumed.

so that the plate didn't look as full, so she wasn't wasting food.

So there's multiple issues with high food portion sizes and actually having a variety will definitely help many people.

I think that would be a great additional attribute within various restaurants and even many supermarkets.

They have a vast range of ready-to-eat options and they're usually single portion sizes and that needs to change as well.

Professor Navid Sattar of Glasgow University in Scotland.

And still to come on the Global News Podcast.