It's no surprise that some methods of weight loss are better for us than others.
Grapefruit diet? Tapeworms? Don't get me started.
But one form of weight loss that seems to continue to get traction in medical establishments is severe calorie restriction with meal replacements. Drastically reduce the amount you eat, and you will lose weight. Presto.
While severe caloric restriction does help with weight loss, at Diet Doctor, we have concerns about the potential negative long-term health implications. A recent study from JAMA Network Open confirmed these concerns.
The trial randomized 100 overweight postmenopausal women to either 12 months of a food-based diet with 30% caloric restriction, or four months of 70% energy restriction in the form of meal replacement shakes and soups, followed by eight months of 30% caloric restriction. Regardless of the intervention, the investigators kept protein stable at 1.0 g/kg of actual body weight. (At Diet Doctor, we recommend 1.2-1.7 g/kg of reference body weight rather than 1.0 g/kg of actual body weight).
After 12 months, the "severe" restriction group lost more weight (15 kg as opposed to 8.4 kg - 33 lbs and 19 lbs) with greater loss in waist and hip circumference and overall fat mass. That would be an excellent result if they lost only fat mass. But that wasn't the case. Instead, they also lost more lean body mass and more muscle in their thighs. Most concerning, however, they also saw a decrease in their hip bone mineral density with trends towards greater loss in the femoral neck and spine. This was despite keeping the protein level the same between the groups.
The study did not mention effects on resting metabolic rate, which prior studies have shown decreases with chronic severe caloric restriction. That is possibly why longer studies on chronic caloric restriction lose their efficacy over time.
We see this as a perfect example of when the number on the scale may not be the best measure of success. Losing weight may not be a meaningful accomplishment if it makes you more prone to a hip fracture or makes you frail in the long run.
That is why we emphasize weight loss in a manner that benefits your overall health. Low-carb nutrition, either with or without intermittent fasting or time-restricted eating, may be more effective for long-term health and weight loss, combined.
So, before you run out and try the grapefruit diet, ask yourself, what will this do for my overall health?
Thanks for reading,
Bret Scher, MD FACC
