Study confirms low-carb and low-fat weight loss diets have same results
ANYONE who’s ever tried to lose weight knows how challenging it is.
But are carbs really to blame?
A major study out of Stanford University found that after an entire year of dieting, those following a low-carb diet lost 6kg and those on a low-fat diet lost 5.3kg. The 0.7kg difference over 12 months was not statistically or clinically relevant, which means they were equally effective.
This is not the first study to compare the two diets, but the fact that researchers carefully monitored the diets of over 600 participants for a full year — which cost over $10 million to design and implement — means it’s by far the most robust and important one to date.
HOW WAS IT DONE?
For this study, 609 overweight participants were split into either a low-carb or low-fat group. In the first two months they had to restrict carb or fat intake to less than 20g per day, respectively. From the third month onwards participants were advised to restrict carb or fat intake to levels they felt they could sustain long-term.
Lead researcher Dr Christopher Gardner told Stanford University: “We advised them to diet in a way that didn’t make them feel hungry or deprived — otherwise it’s hard to maintain the diet in the long run. We wanted them to choose a low-fat or low-carb diet plan that they could potentially follow forever, rather than a diet that they’d drop when the study ended.”
This was a wise move by researchers to minimise the dropout rate, as it turns out that neither group was able to stick to those extremely low starting intakes. By the third month the low-carb group was consuming an average of 97g of carbs per day and the low fat group 42g of fat per day.
All participants were also instructed to attend 22 consultations with a dietitian throughout the year. The emphasis for both groups was to cut back on refined grains, added sugar, and highly processed products, and to eat more whole foods.
“We made sure to tell everybody, regardless of which diet they were on, to go to the farmer’s market and don’t buy processed convenience food crap,” said Dr Gardner.
CARBS AREN’T INHERENTLY BAD
Given the dogmatic approach of many low-carb enthusiasts, most would expect the low-carb dieters to have easily lost more weight than the low-fat group.
After all, it’s the carbs that automatically make us fatter, so restricting them would have the opposite effect, right?
In fact, carbs don’t inherently make you fat, as this study’s results confirm. But we can also look at other cultures with huge carb intakes for living proof of this.
Take for example those from Okinawa in Japan, which has the greatest number of centenarians (people over 100 years old) in the world. Prior to the 1950s, a whopping 85 per cent of an Okinawan’s calories came from carbs, and it remains very high today. Almost 70 years later and so many of them are still slim and healthy (and alive).
There’s also numerous indigenous groups such as the Kitavans of Papua New Guinea who thrived on high-carb diets for hundreds of years. Despite a diet that was 70 per cent carbs (easily over 200g per day), Kitavans had virtually zero overweight people.
If carbs alone are unhealthy, these populations would have had high rates of obesity and/or poor metabolic health, regardless of how active they were.
HOW DO I LOSE WEIGHT THEN?
This circles back to an important element included in the Stanford study.
Regardless if they were in the low-carb or low-fat group, remember that all participants were strongly encouraged to cut back on calorie-dense junk and replace it with nutrient-dense whole food. The result was that they all lost a large amount of weight over the year.
In other words, it’s a low-junk-food diet that is most effective for weight loss — as unsexy as that is. Whether it’s labelled as low-carb, low-fat, paleo, ketogenic or something else is just marketing.