Interval walking is often sold as a weight-loss method. The honest picture is narrower. There is some good evidence that it can reduce body weight and fat, but it comes from a small number of studies, and much of what you will read online goes further than they do.
The clearest evidence: a randomised trial
The most useful study is a randomised trial published in Diabetes Care in 2013. Thirty-two adults with type 2 diabetes were assigned to no training, continuous walking, or interval walking for four months. Both walking groups walked five times a week for an hour, and, importantly, the researchers matched the energy the two walking groups spent.
The results:
- The interval walkers lost an average of 4.3 kg of body weight and 3.1 kg of body fat, including visceral fat around the organs.
- Their aerobic fitness rose by about 16%.
- The continuous walkers, who spent the same energy, showed no change in body weight, fat or fitness.
That last point is what makes the study interesting. If weight loss were simply a matter of calories burned while walking, the two groups should have ended up similar. They didn’t.
Keep the limits in view: 32 people, all with type 2 diabetes, walking five hours a week, which is far more than the 30-minute sessions in the Japanese routine. It is a strong signal from a small study, not a guarantee for everyone.
The Japanese research
A study from Shinshu University followed 666 people of around 65 through four months of interval walking. Body weight, body mass index and body fat percentage all fell significantly, along with blood pressure and blood glucose. The published summary doesn’t give the size of the changes, and the study had no comparison group, so it tells us weight went down but not by how much, or how much of that was due to the walking itself.
The founding 2007 trial, which is the basis of the routine most people follow, was designed to measure fitness, strength and blood pressure rather than weight.
What the evidence doesn’t show yet
- There is no meta-analysis. We could not find a review that pools interval walking studies to estimate an average effect on weight. Any single figure you see quoted as “how much weight interval walking loses” is from one study.
- Little evidence in people without diabetes. The trial with clear numbers was in people with type 2 diabetes. Results in other groups may differ.
- No long-term weight data. The studies ran for four to five months.
What about blood sugar?
In that randomised trial, average and peak glucose readings from continuous monitors fell in the interval group, but HbA1c, the longer-term measure of blood sugar control, did not change significantly. The Japanese study reported that blood glucose fell. If you have diabetes, talk to your doctor or diabetes team before starting, especially if you take medication that lowers blood sugar.
If weight is your goal
- Make the brisk blocks properly brisk. The benefit in the research came from the intensity of the fast intervals. Short phrases, not full sentences.
- Be consistent. Four or more days a week, for months.
- Don’t judge by distance. Interval walking often covers less ground than steady brisk walking, because the easy blocks are slow. That is expected.
- Expect fitness first. Fitness gains were the most consistent result across the studies. Weight changes, where they happened, were modest.
New to the method? Start with the 30-day plan.
Related guides
- Japanese interval walking: the complete guide
- 3-3-3 walking: a 30-day plan
- Interval walking after 60
- Interval walking vs. 10,000 steps
Sources
- Karstoft K, Winding K, Knudsen SH, et al. “The effects of free-living interval-walking training on glycemic control, body composition, and physical fitness in type 2 diabetic patients.” Diabetes Care 2013;36(2):228–236. doi:10.2337/dc12-0658
- Morikawa M, Okazaki K, Masuki S, et al. “Physical fitness and indices of lifestyle-related diseases before and after interval walking training in middle-aged and older males and females.” British Journal of Sports Medicine 2011;45(3):216–224. doi:10.1136/bjsm.2009.064816
- Nemoto K, Gen-no H, Masuki S, Okazaki K, Nose H. “Effects of high-intensity interval walking training on physical fitness and blood pressure in middle-aged and older people.” Mayo Clinic Proceedings 2007;82(7):803–811. doi:10.4065/82.7.803