More people are turning to apps to help them lose weight. But they may not be helping according to new research by the University of Sydney.
"There aren't any guidelines or regulations for the apps," says lead author Juliana Chen, a dietitian and PhD candidate in the Charles Perkins Centre and Faculty of Science.
Chen and her team looked at 800 apps before narrowing it down to 28 apps specifically targeting weight-loss.
Each app was trialled for five days and rated based on the credibility and accuracy of their information, the inclusion of enhanced features (like barcode scanners), and the likelihood of changing health behaviours.
The best ones had "motivational components" including game elements like rewards, challenges, points and feedback.
Overall though, the apps weren't winning over any weight-loss researchers.
There were several glaring problems.
"Less than one third of the apps recorded having an author within the health profession," Chen says.
Less than half the apps included information about healthy eating and the kilojoule measures used in the apps weren't even necessarily accurate.
Some were out by 1001 kilojoules from the actual measure in the food.
Kilojoule counting tools were the main or sole component of many of the apps, yet nutritional science and weight-loss science has moved well past calorie counting in recent years.
"The 'calorie myth' is one of the most pervasive… and most damaging," says Authority Nutrition's Kris Gunnars. "'A calorie is a calorie IS a calorie,' they say… that it doesn't matter whether you eat a 100 calories of candy or broccoli, they will have the same effect on your weight.
"But when it comes to your body, things are not that simple.
"The human body is a highly complex biochemical system with elaborate processes that regulate energy balance.
"Different foods go through different biochemical pathways, some of which are inefficient and cause energy (calories) to be lost as heat.
"Even more important is the fact that different foods and macronutrients have a major effect on the hormones and brain centres that control hunger and eating behaviour."
In fact, the latest research shows that people's bodies respond remarkably differently to the same foods.
Chen says that a personalised approach to eating is the most effective way to address weight and health issues.
"Using an app to support weight loss can be helpful for people who want to get a better idea of the amount of food and kilojoules they are eating each day," she said.
"However, you need to be a highly motivated person to maintain the food logging over a prolonged period of time.
"What leads to more effective weight loss is using an app in conjunction with weight loss counselling from a health professional who can help you with goal setting and identifying barriers and enablers to follow your plan. This kind of personally tailored advice and feedback unfortunately just isn't available in an app."