Low Carb-, Low-Fat Diets Are Equivalent in Benefit for Long-Term Weight Loss  

2-year trial finds no difference in pounds lost, but cutting carbs may be best for heart health 

A new two-year study suggests that a low-fat vs. low carb diet may not matter in the long run: When combined with extensive guidance about eating and exercise, people lost about the same amount of weight whether they were on an Atkins-style, low-carbohydrate diet or a traditional low-fat diet.

Experts suggest that dieters need to be more focused on outcome and not what diet they’re on.

People in both groups only lost an average of about 7 percent of their weight two years after beginning their diet, however those who were on the low-carb diet did get one extra benefit: Their blood pressure and levels of "good" cholesterol improved a bit more than those who cut down on fat. 

There's been ample research into which diet is the best, however this study looks at how diets work over an extended time, which helps to asses validity. 

In the study, funded by the U.S. National Institutes of Health, researchers followed 307 overweight people for two years as they participated in a low-carbohydrate diet -- fashioned after the Atkins diet -- or a low-fat diet that was also low in calories. 

Their average age was 45 and their average body-mass index was 36, meaning they were typically obese, a step beyond simply being overweight. 

Those on the low-fat diet were told to eat 1,200-1,800 calories a day, with fewer than 30 percent of them from fat. Those on the low-carb diet were instructed to eat no more than 20 grams of carbs a day, although they could eat all the fat and protein they wanted. 

In addition to dieting, the participants received guidance about dieting and exercise similar to that offered in commercial weight-loss programs. 

However "good" cholesterol (the heart-healthy kind that you want) grew by about 11 percent in the low-fat group but more than twice that -- about 23 percent -- in the low-carb group. Blood pressure also fell by a greater level in the low-carb group vs. the low-fat cohort. 

Overall, he said, the message of the study is that the diets work about equally well when it comes to weight loss. And what is most important is whether the person sticks to the diet, not the diet itself. 

It also confirms what we have known for years: that it's not fat versus carbohydrates. It's the calories that lead to weight loss.  

But what of the fact that the participants lost a small percentage of weight, on average? While a small weight loss can make a difference in terms of risk factors for heart disease, the study shows it is also difficult to take weight off and keep it off long term, even when you have good support. These people represent what happens in real life, not what we see on the 'Biggest Loser.' Losing weight and keeping it off takes serious commitment. For most, their lifestyles and environments just don't support that kind of commitment.