Low-Carb vs. Low-Fat: Which Diet Is Healthier?

Whether it’s the keto diet, Atkins, or another carb-cutting plan, low-carb eating has become one of the most popular dietary trends. At its peak, around 18 percent of Americans embraced a low-carb lifestyle. On the other hand, low-fat diets have had a strong following since the 1960s, with many people choosing to reduce fat instead of carbs.

So, which is the better or healthier option: low-carb or low-fat?

At First Glance: Similar Weight Loss Results

The debate between low-fat and low-carb diets often centers around weight loss. To uncover whether one approach is superior, scientists have conducted numerous studies.

One notable study, published in Annals of Internal Medicine in 2010, followed 307 overweight participants over two years. Half adhered to the Atkins diet (limited to 20 grams of carbs daily), while the other half followed a standard low-fat diet (30% or less of daily calories from fat).

The findings were surprising. After 12 months, both groups had lost a similar amount of weight—approximately 24 pounds (11 kg). Over the second year, both groups regained some weight, ending with an average loss of 15.5 pounds (7 kg) after two years. This suggests no significant difference between the two diets for weight loss.

However, as Jonny Bowden, PhD, CNS, points out, the results weren’t as simple as “no difference.” Key details were often overlooked in media reports.

Individual Differences Matter

More recent research highlights an important point: weight loss success varies greatly from person to person, regardless of the diet.

A systematic review by the Cochrane Collaboration analyzed 61 trials involving nearly 7,000 participants. Researchers found that both low-carb and low-fat diets led to similar weight loss results. Short-term studies (lasting up to six months) showed the low-carb group losing about two pounds more on average—a statistically insignificant difference. In long-term studies (one to two years), there was virtually no difference in weight loss between the two approaches.

Crucially, results varied widely among individuals. Some thrived on low-fat diets, while others found success with low-carb plans. This underscores that there’s no universal “best” or “healthiest” diet.

Beyond Weight Loss: Overall Health Impacts

While weight loss often dominates the discussion, low-fat and low-carb diets can affect overall health in different ways.

The 2010 study, for example, revealed that the low-carb group had better cardiovascular outcomes initially. After six months, participants following a low-carb diet showed lower triglycerides, lower VLDL cholesterol, and lower diastolic blood pressure compared to the low-fat group. Although these differences diminished by the end of the study, one factor stood out: HDL (“good”) cholesterol levels were consistently 23% higher in the low-carb group throughout the two years.

Additional research suggests that low-carb diets, particularly those high in protein, may have advantages in curbing hunger and improving mood. Studies from 2005 and 2007 found that high-protein, low-carb diets were more filling than low-fat plans, likely due to the satiating effects of fat and protein.

Both diet types have also been linked to short-term reductions in blood pressure, offering potential cardiovascular benefits.

Choosing the Right Diet for You

Ultimately, there’s no single “healthiest” diet. Your success will depend on your unique health needs, preferences, and ability to stick with an eating plan.

As Bowden advises, “The best diet is the one you stick with and the one you have support in doing.”