If you're trying to kickstart weight loss, getting a healthy dose of vitamin D could help.
That's according to a new study that has found taking vitamin D supplements can aid weight loss in obese and overweight people who are deficient in the vitamin.
Previous studies have shown that vitamin D deficiency is associated with developing obesity and the risk of obesity-related complications, scientists at the University of Milan said.
They estimated that in northern Italy, severe vitamin D deficiency ranges from 6% in overweight people to 30%-40% in the morbidly obese. Almost all obese subjects did not have a vitamin D level in the optimal range.
For the study they recruited 400 obese or overweight adults who were split into three groups: those who took no supplements, those who took 25,000 vitamin D units a month, and those who took 100,000.
All participants were put on the same balanced, low-calorie diet.
After six months, only those who took 100,000 units a month achieved optimal vitamin D status but a significantly greater weight decrease and reduction in waist circumference was observed in both groups that took the supplements.
Those who took 25,000 units lost an average of 3.8kg, while the figure was 5.4kg for the 100,000 unit group and 1.2kg amongst those who took no supplements.
Those who took 100,000 units lost 5.48cm on average from their waist, those who took 25,000 units reduced by 4cm and those with no supplementation took 3.21cm off.
The study's authors said: "The present data indicate that in obese and overweight people with vitamin D deficiency, vitamin D supplementation aids weight loss and enhances the beneficial effects of a reduced-calorie diet.
"All people affected by obesity should have their levels of vitamin D tested to see if they are deficient, and if so, begin taking supplements."
Another study being presented at this week's European Congress on Obesity in Prague, Czech Republic, found that living at higher altitude was associated with a lower risk of becoming overweight or obese.
The research, led by the University of Navarra in Pamplona, Spain, analysed more than 9,000 Spanish graduates and discovered that participants living at 456 metres or higher had 13% less risk of becoming overweight or obese than those living at minus 124 metres or below.
They said this was likely to be due to hypoxia conditions, meaning lower concentrations of oxygen in the air, which suppresses hunger due to increasing secretion of leptin.
The authors also speculated that the findings could be due to an ancient adaptive mechanism that aids people to survive at high altitudes where food is not abundant.
"While it might not be realistic to expect everyone to move further uphill to reduce obesity levels, it is encouraging to see this effect occurred at only 450m altitude," they added.