Low-Carb vs. Low-Fat: Which Diet is Best?
Whether it’s keto, Atkins, or another carb-cutting plan, low-carb diets have surged in popularity. At their peak, nearly 18% of Americans followed a low-carb lifestyle. Meanwhile, low-fat diets have been widely adopted since the 1960s, with many opting to reduce fat instead of carbohydrates.
Weight Loss: A Close Comparison
The ongoing debate between low-carb and low-fat diets often revolves around weight loss. To determine which is more effective, scientists have conducted numerous studies.
A notable 2010 study in the Annals of Internal Medicine tracked 307 overweight individuals over two years. Half followed the Atkins diet (limited to 20 grams of carbs daily), while the other half adhered to a low-fat plan (30% or less of daily calories from fat).
After a year, both groups lost about 24 pounds (11 kg). By the two-year mark, some weight was regained, leaving an average loss of 15.5 pounds (7 kg) in both groups. This suggests that neither approach is significantly superior for long-term weight loss.
However, as nutrition expert Jonny Bowden, PhD, CNS, points out, weight loss results aren’t always straightforward.
Why Individual Differences Matter
More recent research highlights that weight loss success varies from person to person, regardless of the diet plan.
A review by the Cochrane Collaboration analyzed 61 trials with nearly 7,000 participants. Short-term studies (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), weight loss between low-carb and low-fat diets was nearly identical.
The key takeaway? Some individuals thrive on low-fat diets, while others do better with low-carb plans. There’s no universal “best” diet—personal preference and adherence play a significant role.
Beyond Weight Loss: Health Benefits and Risks
While weight loss is often the focus, both diets impact overall health differently.
The 2010 study found that the low-carb group initially had better cardiovascular markers, including lower triglycerides, VLDL cholesterol, and diastolic blood pressure. Although these differences faded over time, one advantage remained: the low-carb group consistently maintained 23% higher HDL (“good”) cholesterol levels.
Other studies suggest that low-carb diets—especially those high in protein—may be more effective at reducing hunger and improving mood. Research from 2005 and 2007 found that protein-rich, low-carb diets were more filling than low-fat diets, likely due to the satiating effects of fat and protein.
Both diets have also been linked to short-term reductions in blood pressure, providing potential cardiovascular benefits.
Which Diet is Right for You?
There’s no one-size-fits-all answer. Your ideal diet depends on your health goals, personal preferences, and ability to maintain the eating plan long-term.
As Bowden puts it: “The best diet is the one you stick with and the one you have support in doing.
