Study suggests that replacing one meal with a weightloss shake or bar may be more effective than relying solely on a low-calorie diet
Eating less rich foods may not lead to a smaller waistline. Instead, replacing one meal in a lowcalorie meal plan with a weight-loss shake or bar may be more effective than merely following a low-calorie diet alone, a study by a group of Singapore General Hospital (SGH) dietitians found.
People who are overweight or obese are put on a weight-management programme that includes a low-calorie diet, or such a diet combined with a meal replacement.
“But the effectiveness of meal replacements has not been studied in depth, so we wanted to find out just how useful they are,” said Ms Meina Armanda, a member of the team that included Ms Tan Ai Shan and Mr Tan Lee Boo, all from the Department of Dietetics.
A low-calorie diet works on the principle that if a person consumes fewer calories than he uses up, he will lose weight. The team looked at several studies done to evaluate the effectiveness of a partial meal replacement diet against the standard low-calorie one.
“The results showed that (the people who followed) partial meal replacements had a greater overall weight loss compared with those who relied on a reducedcalorie diet alone,” said Ms Armanda. They found that people on the partial meal replacement plan lost a significant 2.7kg, and 1.6kg more than those on the reduced-calorie diet after three and six months respectively.
There were limitations to the review as not all the trials that the group studied were done in a controlled environment, but the results were promising enough for the team to consider further study. “Going further, we can try to isolate the variables and factors,” she said.
Replacing a meal
Meal replacement shakes or bars are nutritionally balanced products that people trying to lose weight can take in place of some meals. In a diet programme monitored closely by a dietitian, taking appropriate meal replacement products can be useful, said Ms Armanda. “Instead of skipping meals, meal replacements can help people lose weight as they are nutritionally balanced, convenient and easily accessible.”
A diet that includes a partial meal replacement can also help people comply with their diet by reducing hunger pangs and the effects of the so-called yo-yo diet syndrome, which happens when the body responds to an excessively low-calorie intake during a “crash diet” by adjusting the rate at which it burns calories to support the body’s various daily functions. That slower rate of metabolism continues even when the person returns to normal eating, which can lead to weight gain.
“The yo-yo effect happens because crash dieting prompts the body to store fat at a faster rate once a person starts eating normally. This is the body’s protective instinct trying to store reserves for future periods of deprivation,” Ms Armanda said.
Instead of going on a crash diet after binge eating, people should try to lose weight by making sustainable changes to their lifestyles and eating habits, she said.
The SGH team’s study won the first prize in the Best Oral (Allied Health Evidence- Based Medicine) category at the SGH Annual Scientific Meeting in 2011, a conference showcasing the research and studies undertaken by doctors and other healthcare staff at SGH Campus, including Duke-NUS Graduate Medical School.