Weighing up: What’s the bottom line when it comes to weight loss?

In a new study, UniSA researchers have evaluated the affordability of popular diets, comparing them to the recommendations within the Australian Guide to Health Eating (AGHE), and the Mediterranean Diet, finding that costs of cutting your calories can vary by up to $300 per week.

The research shows that the most cost-effective diet was modelled from the AGHE and adapted for weight loss through calorie restriction. This meal plan included all five core food groups and a range of affordable staple items such as breads, pasta, and legumes, as well as lower amounts of animal products.

The diet plans that were most expensive typically restricted multiple food groups and included premium products such as organic produce, protein supplements, low-carbohydrate replacements, and high protein bread.

In Australia, more than 2.5 million Australians had tried a weight loss diet.

Lead researcher Associate Professor Karen Murphy says understanding the costs of weight loss programs is important, especially when people are facing financial struggles and reduced access to fresh produce amid COVID-19 and current floods.

"In Australia, around 12.5 million adults are overweight or obese. That's two in every three adults, or 67 per cent of our adult population," Assoc Prof Karen Murphy says.

"Not surprisingly, interest in weight loss diets continues to rise, yet very rarely are the associated costs of these programs reported.

"In our research, we assessed the weekly costs of seven different meal plans and found that weekly grocery shopping of entire product units cost between $345-$625, which is substantially higher than more than what the average Australian spends on groceries each week.

"Understanding the costs behind the range of diets on offer is important as the financial feasibility of sticking to these programs may be questionable for certain people, including low-income earners.

"Additionally, there tends to be a misconception that consuming a healthy diet made up of the five key food groups, like the AGHE, is too expensive, which it's really not."

The study showed that some of the more expensive diets absorbed up to 13 per cent of disposable income*.

In addition to costs, UniSA PhD candidate, Ella Bracci, says nutrition is also key to starting a new diet.

"It doesn't matter whether you chose keto or carb-free, weight loss is always linked to calorie intake -- if you reduce the number of calories you consume, you will lose weight," Bracci says.

"Some diets purposely restrict certain food groups -- such breads and pasta -- to help change unhealthy habits. But it's also important to realise that the restrictive patterns of some diets can create unhealthy relationships with food and put you at risk of nutritional deficiency if followed without guidance from a qualified nutritionist or dietitian.

"Healthy eating principles such as those within the Australian Guide to Healthy Eating (AGHE) and the Mediterranean Diet place an emphasis on fresh produce and staple foods. While an incorrect perception exists that these can cost more, eating a healthy diet doesn't need to break the bank.

"Shop for specials and mark-downs, buy in season or frozen, dried and canned produce, choose home-brand or non-premium products where possible, and buy in bulk where appropriate.

"Weigh up your options wisely and you can reduce your waistline without cutting into your bottom line."