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When it comes to managing children's obesity, cutting portion sizes and cutting carbohydrates can work equally well – though carb control is tough for many kids, a new clinical trial finds. Many adults have tried to win the battle of the bulge by shunning carbohydrates, especially highly refined or starchy carbs like white bread and potatoes.
But much less has been known about how those eating plans work for kids, including whether they are safe and nutritionally sound – since low-carb diets tend to be relatively high in fat.
For the new study, researchers randomly assigned 100 obese seven- to 12-year-olds to one of three eating plans: one that followed the conventional wisdom of portion control; a low-carb diet; or a "reduced glycemic load" plan that cut down on certain carbs that typically cause surges in blood sugar - like white bread, sweets and white potatoes.
Over one year, all three plans worked equally well in controlling kids' weight gain. The difference, researchers found, was that the low-carb plan was tough to stick with.
Low-carb diets hard for kids
"All of these plans can work," said lead researcher Shelley Kirk, of the Heart Institute at Cincinnati Children's Hospital Medical Center. "But the low-carbohydrate one was really challenging for kids to follow," Kirk said. The diet still helped control kids' weight, she said, because they followed it to an extent - reducing carbs and kiljoules, but not to the strict limits of the low-carb plan.
All of that, Kirk said, suggests that a modified version of low-carb could work well for at least some kids. And the diet based on reduced glycemic load was essentially that: Certain carbs were "unrestricted" - including fruit, vegetables low in starch and 100% whole grains.
More limits were placed on starchy carbs, but they were still allowed.
Improved BMI
Over one year, children in all three diet groups had similar improvements in their body mass index (BMI), a measure of weight in relation to height, after accounting for the fact that they were still growing.
Typically, a child will grow two inches per year before puberty. So for an obese child, simply maintaining the same weight over a year is a "success", Kirk said. A growing child might not see a big weight loss, but what matters is improving "weight status" and overall health, Kirk said.
In this study, published in the Journal of Pediatrics, kids in all three diet groups ended up with healthier cholesterol levels. The low-carb group had a dip in triglycerides, another type of blood fat. And kids who focused on portion control or cutting glycemic load had signs of better blood sugar control.
The bottom line, according to Kirk, is that there are options.
Kids need daily exercise too
For instance, kids could start by trimming carbs to "jumpstart" their weight loss, then switch to portion control for the longer haul – which means more freedom in the foods kids eat, but keeping overall calories in check.
In the end, it comes down to "negative kilojoule balance," or burning more kilojoules than you consume. So kids need not only a healthy eating plan, but daily exercise too, Kirk said.
The children in this study were part of a hospital-based weight loss programme. And it's not clear if their results would translate widely into the "real world." But other hospitals across the US offer program for obese children, Kirk noted. And in other cases, your family doctor may be able to help.
In any case, Kirk said, parents should get some kind of professional guidance in managing their kids' weight, rather than going it alone. And parents should also be prepared to make diet and lifestyle changes themselves. "One of the hardest things is that families need to change," Kirk said. "So think about the eating plan that the entire family can follow and stick with."
(Reuters Health, Amy Norton, March 2012)
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