If you are confused or frustrated by the conflicting claims about whether a low-fat or low-carbohydrate diet is the best for promoting weight loss, you are forgiven. First, we were told that eating a low-fat diet was the best way to lose weight and improve heart health. Then, research suggested that low-carbohydrate diets were better.
Although there are hundreds of diets and weight loss plans you can follow, most fit into one of these two broad categories, reducing calories by cutting back on fats or by restricting carbohydrates.
A recently published study in the Journal of the American Medical Association compared low-fat and low-carbohydrate diets for promoting weight loss. The results say a lot about diets and weight loss in general and I interpret them to suggest that you should focus on food, not nutrients, to achieve your weight loss goal.
This is the topic of my Health & Fitness column in the Aiken Standard this week.

This study was a bit complicated, but it basically compared a low-carbohydrate diet with a low-fat diet for weight loss. After one year, both groups lost about the same amount of weight, showing that both diets were equally effective. This shows that restricting fat or carbohydrates didn’t seem to make a difference for promoting weight loss.
But it might be better to consider that what the two diets had in common is what made them both effective. In addition to the emphasis on fats or carbohydrates, both groups were encouraged to eat less added sugar, more vegetables, and fewer processed foods. It is likely that these factors played such major role in promoting weight loss that they outweighed the effect of which nutrients were restricted.
This isn’t much of a surprise, since eating less added sugar, more vegetables, and fewer processed foods are the three recommendations almost all diets and eating plans have in common. They are also among the very few things everyone seems to agree on when it comes to nutrition recommendations.
When it comes to picking the perfect diet, we should stop thinking on how they differ from one another and focus on what they all have in common. By faithfully following those key recommendations, it almost doesn’t matter what the rest of the diet includes. Avoiding processed foods and added sugar and making vegetables a major part of each meal will lead to healthier choices than simply cutting back on either fats or carbohydrates. In this way, food matters more than nutrients.
This study also demonstrates an important truth about weight loss. The average weight loss wasn’t impressive, only 6 kg in one year, or just a bit over 1 pound per month. I think that most people would be disappointed with this weight change after a year of effort. There was also a big range in weight loss, with some subjects losing over 60 pounds and some gaining about 20 pounds.
Modest average weight loss with some people losing significant weight and others losing very little or even gaining weight is typical for most weight loss programs. What you tend to hear about weight loss programs is the highest expected weight loss—”you can lose up to 40 pounds!” for example, but they don’t tell you what you should really expect. Be skeptical of promises of rapid, significant weight loss. Also be wary of diets that require you to avoid or emphasize certain nutrients like fats or carbohydrates, and remember that the real key to weight loss seems to be food, not nutrients.
