A fitness trend that took TikTok by storm, racking up more than 14 million views, may have some science behind it.
The 12-3-30 treadmill workout, popularized by influencer Lauren Giraldo, promises a fat-burning, low-impact fitness solution: Walk at a 12% incline, at a pace of three miles per hour, for 30 minutes.
But how does it compare to regular running?
A new peer-reviewed study published in the International Journal of Exercise Science compares the 12-3-30 trend to “self-paced” treadmill running.
Researchers sought to determine not just how many calories each method burns, but how the body fuels each workout — specifically, whether the body uses carbohydrates or fat as fuel.
In the study, 16 healthy young adults (male and female) participated in two workouts: one session of 12-3-30 and one session of running at a pace they could maintain for about 20 to 25 minutes.
Both workouts were adjusted to burn the same total number of calories.
The researchers discovered that 12-3-30 took longer to complete than running to achieve the same output.
Running burned calories faster — roughly 13 calories per minute versus 10 calories per minute for 12-3-30.
Maelee Wells Sutton, a certified personal trainer at Crunch Fitness in New York, told Fox News Digital that it is “no surprise” calories are burned faster during a workout with higher aerobic intensity.
“Walking at 12-3-30 is certainly more intense than walking on a flat surface, but is less intense than a run,” she said.
However, 12-3-30 used more fat as a fuel source — about 41% of energy came from fat, compared to 33% during running. Running also relied more heavily on carbohydrates for energy.
Potential limitations
The participants in the study were already exercising at least three times a week for the last three months, according to Sutton.
“That means [the study] doesn’t consider less active individuals, who actually make up a large percentage of the population,” she said. “Essentially, we can’t draw conclusions about how the average person’s body may adapt to these workouts over time.”
The researchers emphasized that the actual fat-burning advantage of 12-3-30 is modest.
Total calories burned still matter more for weight loss than whether you’re burning fat or carbs.
“This study confirms what exercise science has already known: the ‘fat-burning’ percentage of a workout is not the same as total calorie burn,” Sutton added.
Which is better?
If you’re short on time and want to burn a certain number of calories quickly, running seems to be more efficient.
But if your goal is to burn more fat, and you prefer a lower-impact workout, the 12-3-30 method has its benefits, particularly for beginners or those with joint concerns, the study suggests.
The most important thing with exercise is consistency, according to Sutton.
“If a person dislikes running but loves 12-3-30, it’s far better to do that consistently than to force a certain workout that a person rarely completes,” she said.
“Trends should be viewed through both a scientific and personal lens — look to experts for guidance rather than relying on social media.”
