07/19/2011 01:24 pm ET Updated Sep 18, 2011

The BMI Paradox: Thin Kids Eat More Candy

A USDA funded study with partial support by the National Confectioners Association recently published remarkable findings. Kids who eat candy are thinner and have lower BMIs than kids who don't.

The study's authors would like us to believe that this study published in Food & Nutrition Research shows that eating candy is a treat and can be consumed in moderation.

Thinner kids are eating the sweet stuff and show no discernible negative effect. No elevated blood sugar, lipids, or other bio-markers of disease. Sugar candy eaters even show a lower C-reactive protein level, one measure of inflammation.

I have a very different interpretation. I bet the thin kids just get away with it. At least for now.

More Than One Way to Interpret the Data

The USDA data is cross-sectional, a snapshot of our population's health status and food habits. There is no long-term perspective here. The data can show association, but cannot prove cause and effect.

In much of the world today, surviving scarcity is still a metabolic advantage. Some of us seem far better suited to surviving scarcity. We are the ultimate hunter-gatherers, able to store fat readily when food is plentiful.

It occurred to me decades ago that everyone does not enjoy the same metabolic advantages. I've heard more than one researcher suggest that people who don't store fat are the ones with the metabolic defect. What does this say about the thin candy eaters?

A Continuum of Insulin Sensitivity to Insulin Resistance

I suspect there is a wide continuum of relative insulin sensitivity and insulin resistance. At one end are people who are more insulin sensitive, at the opposite end are people who are more insulin resistant.

People who are insulin sensitive seem to burn energy like an incinerator. They eat whatever they want and rarely seem to struggle with weight.

The greater the insulin resistance, the easier it is to gain fat weight, especially when consuming excessive refined starches, sugar and unhealthy fats. It's as if those of us with more insulin resistance are far better suited to hunting and gathering. We survive scarcity. Surviving abundance is proving to be far more challenging.

Factors That Influence Insulin Resistance

Genetics play a role. So do lifestyle factors.

Calories make a difference, but they are not the only factor to consider.

Exercise and overall level of fitness influences how the body uses fuel. Food composition and food distribution influences how the body metabolizes energy. Inadequate sleep and other sources of stress influence energy metabolism. Prescription and over-the-counter pharmaceuticals impact metabolism. So do alcohol, nicotine and other recreational drugs.

What About Children?

So what could be happening when thinner children eat more candy than heavier children? Are these children better able to navigate the "calories in, calories out" balance over time, as the authors suggest? I don't think so.

The authors note that "overall diet quality was very poor in all groups, regardless of whether candy was consumed." This is an important point. Both thin and heavier children are basically eating the same thing. The thin kids were even reported to eat more calories.

Is Targeting Child Obesity the Best Approach?

I suspect that the thin kids merely get away with eating candy and a poor diet -- for now. Maybe they are merely more insulin sensitive than their heavier counterparts. We don't know, but we may want to consider the implications.

I question our current approach, specifically identifying and treating heavier kids. Targeting child obesity as if it is a moral failure, a matter of making better food choices or a disease is short-sighted at best.

There are enormous social and emotional costs when we assume just the heavier kids need to eat differently. There is just as much damage when we let thin kids think they can eat whatever they want. Inevitably they grow up and can't.

Thin kids may never become obese adults. But they certainly can become metabolically "obese" and develop diabetes, hypertension and other cardiovascular disease, even cancer.

Time to Rethink the Goal: Health at Every Size

Body size is not a good litmus test for what one gets to eat. All children deserve to experience the energy and well being that is possible by eating a healthful diet. All children deserve an opportunity to learn what balance of protein, carbohydrates and fat works best for them. All children deserve an approach to food that doesn't increase their risk of lifestyle disease states as adults.

We know obese children are more likely to be obese as adults. It is also true that most overweight and obese adults were thin as kids. From 1971-1974 only 5 percent of children were identified as obese. Over 60 percent of adults are considered overweight or obese today. Maybe we need to rethink our strategy.

We can start by focusing on health at every size. Decreasing incidence of child obesity is important, but not more important than creating a food environment where all children can thrive. Ultimately we are faced with a dilemma: Will we be more successful treating individuals or transforming the physical environment and social conditions that contribute to the problem?