When it comes to weight loss, many of us have dabbled in the latest diets. But whether you're cutting carbs (the horror!) or keeping to keto, new research shows that diet trends can shrink more than just your waistline, with your bank account also losing some of its bulk.
In a new study, published in the journal BMC Public Health this week, researchers from the University of South Australia evaluated the affordability of popular diets. The team compared fad regimes to the widely lauded Mediterranean diet, as well as recommendations within the Australian Guide to Health Eating (AGHE).
The study found that the cost of cutting calories can vary by up to AU$300 (NZ$323) per week - and many popular diets can leave a hefty hole in your hip pocket.
The research showed 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.
More than 2.5 million Australians across the country had tried a weight loss diet, the researchers found.
Understanding the costs associated with weight loss programmes is imperative, particularly as people face financial struggles and reduced access to fresh produce amid the ongoing COVID-19 pandemic, lead researcher Associate Professor Karen Murphy said.
"In Australia, around 12.5 million adults are overweight or obese. That's two in every three adults, or 67 percent of our adult population," Assoc Prof Murphy said.
"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 AU$345 and AU$625, which is substantially higher 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 programmes 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 also showed that some of the more expensive diets absorbed up to 13 percent of disposable income, based on the average pre-tax earnings of an Australian in 2020.
In addition to costs, University of South Australia PhD candidate, Ella Bracci, noted that nutrition is also key to starting a new diet.
"It doesn't matter whether you choose 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 said.
"Some diets purposely restrict certain food groups, such as 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 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."
According to the nonprofit academic medical centre Mayo Clinic, the Mediterranean diet is a plant-based, healthy-eating plan that incorporates the traditional flavours, eating habits and cooking methods of the cuisines of countries that border the Mediterranean Sea - such as Spain, France, Italy and Greece.
The diet has been hailed as a heart-healthy way of eating, with numerous studies confirming that Mediterranean cuisine helps prevent heart disease and stroke. Plant-based foods, such as whole grains, vegetables, legumes, fruits, nuts, seeds, herbs and spices, are the foundation of the diet. Olive oil is the main source of added fat, while fish, seafood, dairy, poultry - and wine - are included in moderation. Red meat and sweets are eaten only occasionally.
Living the Mediterranean way includes building meals around vegetables, beans and whole grains, eating fish at least twice a week, using olive oil instead of butter in preparing food, and serving fresh fruit for dessert. Of course, physical activity is also important.