Does low-fat put your kids at high-risk for obesity?

Most Americans firmly believe that a low-fat diet is the best way to achieve and maintain a normal body weight. But a growing body of research indicates that far from being ideal, low-fat diets may actually be contributing to our nation’s obesity crisis.

Low-fat diets received a tacit stamp of approval in 1992 when the USDA introduced its “food pyramid.” According to the USDA guidelines, we were urged to use fats, oils and sweets “sparingly” (the top of the pyramid), and to build our diets around breads, cereals, rice and pastas (the base of the pyramid).

A central idea behind a low-fat dietary regimen is that a calorie is a calorie is a calorie. In other words, 100 calories of French fries is equal to 100 calories of mixed greens. The trick to staying lean, then, is to keep calorie consumption low or energy expenditure high. That helps explain the explosive growth of calorie-counting diets, gyms and exercise products. But it doesn’t shed light on the fact that after decades of low-fat diets, American waistlines continue to grow.

The answer to that mystery might be found in new research that challenges the old “calories-in-calories-out” viewpoint. Over the past decade, study after study has confirmed that, in fact, all calories are not created equal. It appears that our bodies respond differently to calories from highly processed carbohydrates, like white flour and sugar. These foods cause spikes of blood sugar and insulin, which prompt the body to retain fat rather than burn it off.

So the unfortunate irony is that a diet built on a foundation of breads, cereals, rice and pastas—the base of the pyramid—may actually undermine attempts to maintain a healthy body weight. The USDA addressed this issue a year ago when it replaced its food pyramid with My Plate ( The new guidelines call for a diet that is 50% fruits and vegetables and only about 25% “whole grains.”

The latest research has also prompted a spike in the popularity of “Atkins”-style diets that promote zero or minimal carbs (including many fruits and vegetables) while allowing for liberal portions of fats and proteins. Some adherents of these diets report impressive weight loss on palate-pleasing meals of bacon, eggs and steak. While these diets can provide dramatic metabolic results in the short run, their long-term effects on health and mortality are questionable at best.

Again, the best diet is one that provides optimal health, not optimal weight or waist size. A good eating regimen is also realistic. Most people have a hard time sticking to a strict no-carb diet. And eliminating a bunch of fruits and vegetables because they contain carbs means missing out on a ready source of important vitamins and minerals.

The solution, as usual, calls for moderation and common sense. For starters, any diet regimen should eliminate as many highly processed carbohydrates and added sugars as possible. How can you identify highly processed foods? Some general rules of thumb are:

  • If it comes in a box, there’s probably a better alternative.
  • If the list of ingredients runs on for more than two or three lines, it’s most likely a highly processed food.
  • Added sugars are found in virtually all sodas, fruit drinks, candies, cakes, pies, etc.
  • Known aliases under with added sugars hide include sucrose, fructose, dextrose, corn syrup, maltose, nectar, brown sugar, cane juice and fruit juice concentrate.
  • If an ingredient contains the word “white,” (white flour, white rice, white pasta, etc.), either avoid it and try to find an alternative (whole-grain pasta, brown rice, soy flour, etc.)

Even modest dietary changes can make a substantial difference in your baseline weight and overall health. If you take it a step further by eliminating sugary drinks and replacing refined carbs with fruits, beans and nuts, you’re well on your way to optimal health for you and your family.

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