The obesity epidemic is growing, and experts are calling it a “system wide” problem with over-processed food dominating our lives. Only three percent of Australians meet the Australian Dietary Guidelines recommended five serves of vegetables (at 75g per serve, which is about half the weight of a baseball) new ABS data shows.

And one in three Australian adults (67%) are overweight or obese according to the last national health survey.

If you’re above a healthy weight there’s a higher risk of diabetes, cardiovascular disease, some cancers, and possibly more severe Covid-19 symptoms according to a paper in the US on the impact of nutrition on virus susceptibility.

Australians don’t eat enough fruit and vegetables but consume too many salty foods, ABS data released in June shows.

The study measured sales data but could only make estimates of the actual food eaten without food consumption data from restaurants, fast-food establishments or food wastage.

Professor Stephen Simpson, biologist and co-author of ‘Eat Like the Animals’ has spent the better part of 30 years studying nutrition and dietary causes of obesity in humans. He said the majority of people not eating enough serves of the necessary food groups is likely because about 50% of Australians’ calorie intake comes from ultra-processed foods instead.

These are things like soft drinks, chips, chocolate, ice-cream, or chicken nuggets.

This may seem like an obvious reason for the increase of obesity around the world but it’s a very complicated issue, let’s take a closer look.

The proportion of overweight and obesity in adults rose from 57.2% in 1995 to 66.4% in 2018. Although it appears that the proportion of overweight people started to drop from 2007 this is likely because they moved to the obese category instead.

“What we can see if you start to understand the biology of overeating, overweight and obesity is that it’s a tremendously powerful biology that is in most cases not simply ignorable or overridable by using your willpower,” Simpson said.

The amount of protein we consume has a huge effect on our health and body weight. We have a set target of protein to reach each day, of about 15% so that when combined with other important nutrients we can survive at our healthiest.

There are two ways that our protein target ties in with the obesity epidemic.

“First, you’ve got protein diluted by large quantities of industrially produced fats and carbohydrates, and the geometry of that is fairly straightforward. You need to eat more calories as fats or carbs (it doesn’t matter which) to get to your protein target,” Simpson said.

Even if you have an abundance of protein available, if it’s swamped by lots of fats and carbs then on average you will eat more calories then you actually need to reach your target.

The second way Simpson said is, “Anything that causes the protein target to go up will make you have to eat more calories in a given low protein environment then if the target was a bit lower.”

Simply, the higher your protein target, the more excess calories you’ll have to eat in order to reach it.

There are a few reasons your protein target might be set too high. For example, an elite athlete or bodybuilder will have an above average target because they need more protein to maintain muscle. But if they move to a more sedentary lifestyle, then their target will remain high for a while and they may become overweight.

More worryingly Simpson said, “Your protein target may be set too high even at birth because of what your mother and father ate pre-conception and during pregnancy.”

“Similarly, if you go on a higher then optimal protein diet very early in life, we think that might set the target too high and it explains why some of the infant formula fed babies have higher risk of obesity later in childhood and adolescence.”

However, a problem with most explanations for the obesity epidemic is that if the issue was just eating too many calories then the expectation is that the population would become increasingly overweight and then plateau and stop.

Simpson says this is because the bigger you are, the more calories you need. If you continue to eat more calories than eventually, you’re going to need all of them because there’s more of you.

“Instead of going up and plateauing the obesity epidemic has accelerated and what we realised is that there must be something that’s moving further and further away that we’re essentially chasing in our biology, and we realised that’s the protein target going up,” Simpson said.

Jane Martin, the Executive Manager of the Obesity Policy Coalition and President of the Australia New Zealand Obesity Society advocates for policy and regulatory reform, with a focus on food marketing, labelling and pricing measures.

Martin says the ultra-processed food industry frames the issue as a problem of parents and individuals, but it’s a system problem.

“These companies aren’t really paying for the harm that they cause so that’s where a health levy on sugary drinks comes in for example,” she said.

“Some of the money that these products are imposing such as on dental health and leading to overweight and obesity are being recouped for the cost of treating these diseases.”

After tobacco smoking, diet is the leading cause of the burden of disease followed by overweight and obesity at number three. Altogether this is a really big source of death and disease in our society.

Martin suggests stronger warnings on food packaging about high sugar, salt or fat content and stricter junk food advertising laws would be helpful in tackling the issue.

“Reducing exposure and the power of promotion so protecting children and putting a levy that tells people two things – It tells them the products’ harmful and it raises the price which stops a lot of people from buying those products,” she said.

Martin says she doesn’t think people know what’s healthy anymore outside of fruit and veg, there’s a lot of confusion about ready-made meals and manufactured foods like muesli bars. This is partly because the Australian Government haven’t promoted the Australian Dietary Guidelines as effectively as they could have.

“[Australians] are eating this food because it’s easy and it’s a much simpler decision. It’s hard to eat healthily, it’s a challenge for most people,” Martin said.

Main image by Dan Gold on Unsplash and all graphs created by Brianna O’Rourke.