A leading UK doctor is warning that quick-fix new year diet pills could lead to unplanned pregnancies.
Professor Stephen Powis says using pills and detox teas have a 'slim chance of success' - and can cause heart problems or interfere with contraceptives.
The NHS England's medical director says people should instead lose weight 'gradually and safely'.
"New Year's resolutions are a great time to make a change, but the reality is there's a slim chance of success with diet pills and detox teas - and people could end up doing more harm than good," said Professor Powis.
Meanwhile, people are being reminded to set realistic New Year's resolutions - and not to aim for too many.
Targets, like losing weight and quitting smoking, are common - but few are still kept later in the year.
Gerry Duffy is the author of a book on achieving goals - he says setting targets like losing three stone in weight may be too high to announce early on:
"Maybe I can lose 20% of that in a month or two - and then maybe I'll announce to the world that I have a really big goal. Even though that might have been the goal all along.
"The challenge is if we set ourselves up for such a big goal and even achieve 90% of that, our psychology might be that 'gosh, I lost two-and-a-half stone but I wanted to lose three' so we end up not putting that value on ourselves."
