Atkins low-carb dieting has surged in popularity the past few years. Now it’s rapidly evolving from a weight-loss diet into a low-carb lifestyle that could actually make us fatter.

Short-term effects appear safe and effective

First, let’s look at the Atkins diet, which has aroused fierce debate since its 1972 debut. The plan limits carbs to 20 grams per day (80 calories’ worth) during the initial 14-day Induction Phase and 50 grams during the Ongoing Weight-Loss Phase. It also permits liberal amounts of meat, eggs and cheese high in saturated fat and cholesterol.

However, several recent trials show Atkins may well be a safe and effective weight-loss option for short-term use—six months up to a year) for some people. (But, as with any major dietary change, start it only after consulting with your doctor.

In the Atkins trials, heart-disease risk factors improved about as much as with a high-carb/low-fat diet and even more so for those obese participants who got little exercise. Atkins also yielded greater weight loss at six months (15.2 pounds versus 6.8 pounds), but the difference narrowed and was no longer significant at 12 months.

How does it work?

How does Atkins work? Research suggests its weight-loss effect has little to do with “ketosis,” which begins a day or two into the diet once the body uses up its stored carb reserves and is forced to burn ketones (a byproduct of body-fat breakdown.) That was formerly thought to reduce hunger and enhance fat loss. In addition, the jury is still out on the claim that the diet’s reduction in blood-sugar swings results in lower appetite.

Rather, the Atkins diet may succeed mainly by helping reduce calorie intake in two ways. First, its carb limits greatly restrict food choices. That blocks a major trigger to overeating, because monotony lowers food intake, while variety boosts it.

Second, Atkins, like many weight-reducing diet plans, makes impulse eating more difficult by placing off-limits many of our favorite “quick-grab,” high-calorie snack foods like chips, crackers and cookies. Even routine eating takes more thought and planning.

Long-term concerns

So, what about the improvement in heart-risk indicators despite eating all that saturated fat and cholesterol? Research shows as long as you’re losing body fat while on Atkins (or any diet), these two bad guys appear to lose their negative effects for most people.

However, once weight loss stops, excessive saturated fat and cholesterol may once again become risky. That’s one reason why a long-term low-carb diet high in meat, eggs and cheese may raise health risks. Another is that very low-carb diets simply lack enough healthy carb sources— such as vegetables, whole grains, fruits, and beans—shown to reduce the risk of heart disease, stroke, cancer and diabetes.

From weight loss to lifestyle

The recent positive media reports on Atkins and the food industry’s quick response to profit-boosting trends are rapidly turning short-term low-carb dieting into a potentially more risky and even weight-promoting low-carb lifestyle.

Supermarkets now offer hundreds of new, specially processed (and higher-priced) low-carb foods with labels such as “carb-aware” and “carb-smart.” Even naturally low-carb foods are being re-labeled to tout this fact.

Restaurant chains are recasting their high-calorie, high saturated-fat foods as “low carb” or even “Atkins approved.” And new multivitamin formulations dubiously claim to supply what’s missing in a low-carb lifestyle and help you burn the extra fat and protein you’re eating.

This rapid growth and promotion of low-carb food choices may even sabotage the Atkins diet’s major calorie-limiting mechanisms mentioned above. Remember that food variety may promote overeating, especially when you ignore calories

“Net-carb” labeling

Most low-carb foods now list the grams of “net carbs” derived by taking total carbs and subtracting those that have little impact on blood sugar, even though some contain calories. The debited carbs include ordinary fiber (no calories,) “fermentable carbs” (about half the calories of ordinary carbs,) and sugar alcohols (five percent to 75 percent of the calories.)

This net carb-labeling trend encourages us to count carbs instead of calories. Yet study after study shows that cutting overall calories is what really matters for weight control, not whether they come from carbs or fat. Indeed, many new low-carb foods have only slightly fewer calories than their full-carb versions.

Reducing calories

All this begs the question of what to do about carbs and fat when reducing calories. After all, they make up the bulk of our calories. The best place to cut carb calories is soda, juice drinks, and other items high in added sugar, as well as white flour and other refined grain foods.

Fat calories are best cut from foods high in saturated fat and trans fat (the latter found in partially-hydrogenated oils or vegetable shortening): fried foods, high-fat dairy foods, fatty meats, butter, stick margarine, and many types of popcorn, cookies, crackers and chips.

By David Leonard, UNH Extension Educational Program Coordinator, Food and Nutrition

For more information

• Find out your daily calorie needs
• Why are we eating more food, yet burning fewer calories these days?
• Find out the pros and cons of popular weight-loss diets
• Assess your diet and physical activity level Click on Interactive Healthy Eating Index