A lot of us fall back on dieting apps to make staying in shape easier but new research has revealed that often, they just don't work.
One of the main reasons is because they often fail to provide motivational support and tips on changing behaviour.
A study into 30 of the most popular diet apps, which can be downloaded on to portable devices such as smartphones and tablets, found most included few or no behavioural weight-loss strategies.
Researchers in America also discovered that free apps were just as useful as premium downloads.
Weight loss expert Sherry Pagoto, associate professor of medicine at the University of Massachusetts Medical School, said: "Apps do include evidence-based behavioural strategies, but only a narrow range.
"Strategies that often were missing are ones that help patients with adherence and motivation."
Behavioural weight-loss strategies that are evidence-based - meaning they have been scientifically researched and found to be effective - include stimulus willpower control, problem solving, stress reduction and relapse prevention.
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Researchers were also interested in determining whether apps incorporate technology features to enhance behavioural strategies.
Enhancements include barcode scanners that can be used in a supermarket to instantly get nutritional information, social networks where users can encourage and support each other, email and text reminders, and calendars for scheduling exercise and tracking food intake.
Martyn Landi, reviews editor with British-based Apps magazine, said weight-loss software should not be used in isolation as a means of fighting fat.
"A little bit of common sense is needed with these apps," he said.
"There are a few weight-loss apps, mostly driven towards the fitness tracker-style download and those offering recipe ideas.
"But apps are becoming more sophisticated as they develop. We are seeing the introduction of some motivational techniques in fitness tracker downloads where messages can be pre-recorded so that they play while a person is jogging."
The tech expert also said there was scope for further developments within the market.
"Apps are becoming increasingly geared to our lifestyles," Mr Landi said.
"Smartphones are so prevalent, they are such a part of our lives that almost every aspect of our lifestyle is being catered for with apps.
"Many now have a 'sharing' facility, meaning users can compare their progress with friends, so I think we are seeing some degree of motivational function already."
The two top-rated apps, according to the study, are MyNetDiary PRO (paid-for) and MyNetDiary (free).
Dr Pagoto said: "Free apps were just as likely as paid apps to include evidence-based strategies. That's the good news for the consumer.
"Where we're hoping the next generation of apps can do better is in incorporating some of those strategies that help the user who might not be so good about entering their diet every day and staying on track with their goals."Suggest a correction