For those debating between low-fat diets and low-carb ones, according to a new study by the National Institutes of Health, reducing dietary fat is better for weight loss than reducing carbohydrates,
For the study, scientists put ten obese men and women in a hospital for two different fortnight stays. For both stays, they were given identical exercise routines and their collective calorie intake was reduced by about 30 percent.
LOW-FAT DIETS VERSUS LOW-CARB DIETS STUDY
During one stay, calories were reduced by cutting the proportion of carbs; in the other, a similar amount of fats were reduced. Researchers found that 3.1 ounces were lost daily by cutting out calories over a six-day period, and only 1.9 ounces were lost daily by cutting out carbs.
“Our data and our model suggest that the body doesn’t care that fat calories were cut,” Kevin Hall, a National Institutes of Health researcher, told Reuters Health in an email. “It just kept burning the same amount of fat as it did before which led to a substantial imbalance between the fat eaten and burned and therefore body fat loss.”
NOT ALL CALORIES ARE CREATED EQUAL
In the long term, it’s likely that the difference between the fat calories and carb calories will be minimized by the body. In a statement, Dr. Hall said “Our results showed that, actually, not all calories are created equal when it comes to body fat loss, but over the long term, it’s pretty close.”
Hall admitted that the study was imperfect and warned against making “sweeping conclusions” with the data. Only 19 people were used in the study because the research was expensive to conduct, their diets would not necessarily be easy to follow over a long period of time, and the food they consumed did not resemble the kind used in most diets.
The study, which was published in the journal Cell Metabolism, also confirmed that cutting carbs decreases insulin production and increases fat oxidation.
ENERGY IS THE BIGGEST FACTOR
However, Tufts University nutrition researcher Susan Roberts said in an article published with the study that its results are proof that diets low on carbs are not superior to those low on fat. “Basically what the results say is that overall energy balance is the biggest factor – how do you cut calories in what you eat,” Roberts told Reuters.
