Swedish researchers monitored 6,640 overweight or obese people (mostly women) who chose either a very-low-calorie diet (500 calories a day) or a low-calorie diet (1,200 to 1,500 calories a day) for three months. Then both groups entered the same weight maintenance phase—including exercise and diet advice—for nine months.
At the end of the 12 months, the very-low-calorie dieters had lost more weight (24 pounds) than the low-calorie dieters (18 pounds). However, there were 48 gallstones requiring hospital care in the very-low-calorie dieters, but only 14 in the low-calorie dieters.
What to do: If you’re thinking about going on a very-low-calorie diet, consider gallstones as a possible downside. Although rare, they were roughly three times more common than on the low-calorie diet. (And don’t assume that a very-low-calorie diet leads to greater weight loss. It’s possible that the more-ambitious dieters picked that option.)
Source: Int. J. Obesity 2013. doi:10.1038/ijo.2013.83.
Other relevant links:
- Are they equally effective for weight loss? See: Walking vs. Running to Lose Weight
- Do you want to lose weight and still feel satisfied? See: Diet and Weight Loss: Trim Calories Per Bite to Trim Pounds
- What is high-intensity interval training and what are benefits of doing it? See: Diet and Weight Loss: Get Fitter Faster with Interval Training