While many people are able to lose weight successfully, the even greater difficulty is in keeping that weight off. In fact, less than 20% of people who lose 10% of their weight are able to keep it off for a year. Does the amount of weight lost, or the rate (speed) of weight loss, predict who is more likely to regain their weight?
A recent systematic review analyzed the results from 43 studies to address these questions. These were studies of lifestyle intervention in which participants had lost at least 5% weight and regained at least 2% of that weight.
They found that a greater weight loss was a predictor of weight regain. Why? Well, we know that with weight loss, there are profound changes in our hunger and fullness hormones that drive us to eat more to regain weight, as well as a reduction in our energy needs (remember that our bodies are machines evolutionarily built to survive famine). The greater the weight loss, the more heightened these defenses become to drive weight back up.
They also found that a faster weight loss was a predictor of weight regain, even more so if the amount of weight loss was larger to begin with. This means that weight loss strategies that result in fast weight loss, and especially if it is fast weight loss of larger amounts, are less likely to be sustained over the long term.
Changes in body composition play a role as well (much more on this in the paper for interested readers).
So what is the real life bottom line here?
- Large amounts of weight loss are not required to improve health, and smaller amounts of weight loss are easier to sustain. A sustained weight loss of just 5% reduces the risk (or improves) many metabolic health complications of obesity.
- Weight loss should be slow and steady, not dramatic and fast. Any program that is resulting in fast weight loss is unlikely to be a permanent lifestyle change, and temporary changes are usually not met with long term success. A gradual and sustained weight loss of 1-2 lb (0.5-1kg) per week is recommended.
Dr Sue Pedersen www.drsue.ca © 2019
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