Walking for weight loss: what Herman Pontzer's research shows

Walking on its own usually changes weight less than people expect. Herman Pontzer's research suggests why: after a few months of more activity, the body spends less energy elsewhere, so the total it burns each day stays in a fairly narrow range. Walking still earns its place. People who stay active tend to keep lost weight off better, though that's a link, not proof, and in Pontzer's words, diet is for your weight and "exercise for everything else." So walk for those reasons, start with ten minutes, add strength work, and let your eating habits do most of the work on weight.

Pontzer went to northern Tanzania to measure something no one had measured before: how many calories a day hunter-gatherers burn. His team found Hadza men walking about 19,000 steps a day and women about 13,000, on top of the other work they do (NPR Shots). The Hadza, he told the Ologies podcast, "get more physical activity in a day than most Americans get in a week." And yet: "despite that, despite that, to our enormous surprise, because we did not expect this going in, they burn the same number of calories every day as Americans do" (Ologies).

That surprise became the center of his book Burn (Penguin Random House), and it explains a common experience: weeks of brisk walks, and a scale that barely moves. Yet Pontzer calls himself "on Team Exercise, 100%" and says "we have to think about exercise and diet as two different tools for two different jobs."

Why doesn't walking move the scale much?

1. Know what the body does with the extra

Most people picture simple addition: walk more, burn more, lose more. Pontzer's research supports a constrained model instead. In a 2016 study, his team measured energy burned over a week in 332 adults aged 25 to 45 in Ghana, South Africa, the Seychelles, Jamaica and the United States, using a lab method based on labeled water, and compared it with activity tracked by wearable sensors (Pontzer et al., 2016). At low and moderate activity, more movement went with more energy burned. Among the most active, roughly the top 30%, it leveled off. The study looked at people at one point in time, so it shows a pattern across people, not what happens inside one person who starts walking.

Pontzer describes the change over time this way: "If you or I started an exercise program tomorrow, we will burn extra calories from that exercise for a while. But after a couple of months, our bodies will adjust so that we're spending about the same energy every day as we were before we started the exercise" (NPR Shots). Exercise still burns calories, he explains; the body spends less elsewhere to make room for it. He adds a caution on A Whole New Level, the podcast of Levels, a company that sells glucose monitors: "I'm saying it'll be less than you expect, but it might be a bit more." He also says people vary a fair amount, in ways researchers don't yet understand (A Whole New Level).

2. Expect a small number on the scale

Trial results fit that picture. A 2024 review pooled 116 randomized trials of supervised aerobic exercise, such as walking or running, in 6,880 adults with overweight or obesity, average age 46 (Jayedi et al., 2024). Each 30 minutes of aerobic exercise a week went with about 0.52 kg less body weight (a little over a pound). At 150 minutes a week, the estimate was about 2.8 kg (around 6 pounds). Most trials were short: only two lasted longer than 48 weeks.

Walking programs on their own look similar. A review of nine pedometer-based walking programs that didn't change diet, with 307 people in all, found an average loss of about 1.3 kg (under 3 pounds) over a median of 16 weeks (Richardson et al., 2008). People added from slightly under 2,000 to more than 4,000 steps a day. The review compared weight before and after, and most of its studies had no comparison group, so take the number as a rough guide.

Kevin Hall, a former senior investigator at the US National Institutes of Health, calls the weight results from exercise trials "a little bit disappointing, especially for women" (Guardian Science Weekly, 7:31). Yoni Freedhoff, a Canadian doctor who helps people manage their weight, puts it this way: "people can lose weight with exercise, it's just that they tend not to lose weight with exercise" (Science Vs).

Two common explanations don't hold up well. "You're gaining muscle": Freedhoff says casual exercisers don't gain much. "You eat it all back": a European review of trials in adults with overweight or obesity found training didn't raise average food intake from the start, or by much against people who didn't train (EASO, 2021).

"We have to think about exercise and diet as two different tools for two different jobs." Herman Pontzer

So why walk at all?

3. Walk for keeping weight off

Hall's advice is to keep moving and stop scoring it on the scale: "Just don't tie the amount of exercise that you're doing to the weight loss" (8:36). Pontzer makes the same point from the other side. Food has the bigger effect on losing weight, he says, but "once you are able to lose weight and get to a set point where you want to be, exercise is really key in keeping yourself there" (NPR Shots). His "set point" is a rule of thumb; he says the idea "doesn't hold super well scientifically" (A Whole New Level).

The evidence for this is a link, not proof. The European review found that adults who do large amounts of activity, 250 minutes a week or more, are more likely to keep weight off, based on looking back at trial data (EASO, 2021). The American College of Sports Medicine found the same link in studies that followed people, and noted that no well-designed trial had tested it (ACSM, 2009). Our article on weight loss plateaus covers what else helps people keep weight off.

4. Walk for everything else

Pontzer calls exercise "the rhythm section of your body", the part that keeps everything "on the same beat" (NPR Shots). Freedhoff, who says exercise isn't good for weight loss, is also, in his host's words, "pretty much exercise's biggest fan": asked to name the single healthiest thing a person could do, he picks exercise (Science Vs).

If you walk only to lose weight, a stalled scale can end the habit. If you walk because it clears your head, gets you outside and goes with keeping what you've changed, a slow week on the scale gives you no reason to stop.

How do you start walking in a way you'll keep?

5. Start with ten minutes, and count every minute

The World Health Organization advises adults to get 150 to 300 minutes of moderate activity a week, and says "some physical activity is better than none" (WHO, 2020). Its 2020 update dropped the old rule that activity had to come in bouts of at least ten minutes to count, because activity of any length is linked with better health.

So treat WHO's range as where you're heading, not where you start. Ten minutes a day is a fine first step: a walk after lunch, the long way to the station, a lap of the block before dinner. Add a few minutes a week if it feels easy. If you sit most of the day, short walks spread through it, plus a few minutes on your feet every hour or two, count too.

6. Choose the kind of moving you'll keep

Walking is the easiest place to start, but it doesn't have to be walking. US public guidance suggests trying a few kinds of activity and keeping what "you enjoy most and can fit into your life," because those are "easier to stick with over the long term" (CDC). Pontzer is blunt about it: "if you don't like it, you're not going to do it" (A Whole New Level).

Here's a quick way to choose. Think of two kinds of moving: one you do now or did before, and one you'd like to try. Ask three questions of each:

• Do I enjoy it?
• Can I get to it, at a cost I can manage?
• Does it fit my week, with work and the people who rely on me?

Pick the one with more yeses. Then decide when it happens (after lunch, after the school run) and pick a busy-day version, the smallest bit that still counts: a ten-minute walk, the stairs instead of the elevator, five minutes of stretching at home. Tying the walk to a set time and place is an if-then plan; our guide to implementation intentions explains why that helps.

7. Add strength work twice a week

WHO advises adults to do muscle-strengthening activity on two or more days a week (WHO, 2020). It matters most while you're changing how you eat. The European review found that strength training during a weight-loss diet cut the loss of lean body mass, and aerobic training didn't (EASO, 2021). In six trials with older adults with obesity who were cutting calories, adding strength training three times a week kept more lean mass, with similar fat loss (Sardeli et al., 2018).

You don't need a gym. Dumbbells, resistance bands or your own body weight all count: standing up from a chair ten times, push-ups against a wall, a few squats while the kettle boils.

8. Judge the walk by whether it happened

A fitness tracker's calorie count won't help you here. Asked how good those estimates are, Pontzer said: "It's a little bit better than a random number generator. Just a little" (Ologies). Most of what you burn each day goes on keeping your body running, which a step counter can't see.

The better measure is simpler: did the walk happen? If it didn't, ask what got in the way and change one thing. If you forgot, tie it to something you already do. If plans changed, move it to another time. If you didn't want to, let it wait and pick it up later.

Walk for the reasons that last

The Hadza walk most of the day and burn about as much as people in the West. Pontzer didn't conclude that their walking was wasted. He concluded that the body is more adaptable than the calorie math suggests, and that "the body will just push back if you push too hard" (NPR Shots). People who keep moving tend to keep lost weight off better. For the eating side, start with how to lose weight sustainably, always feeling hungry and the best diet question. Today, pick your ten minutes for tomorrow.

To plan this around your own day, try the 1h Protocol to Lose Weight Sustainably. It's practical education about everyday eating and movement habits. The first chapter is free: a few short questions find the pattern your eating follows and give you one thing to do tomorrow. The full program takes about an hour. It walks through one day with you at your own times, including the kind of moving you choose, the days it fits, a busy-day version and strength work twice a week. You leave with a page of the habits you chose, a plan for the "just one" moment, a card for your lock screen, a fourteen-day sheet, and days seven and fourteen in your calendar. You can write your own goal, a weight goal included; the program never sets a target, calories or a diet. Short check-ins follow by email on days 1, 7, 14 and 30. Start free

Frequently asked questions

Can you lose weight just by walking?

A little, on average. Walking programs that didn't change diet were followed by about 1.3 kg (under 3 pounds) of loss over a median of 16 weeks (Richardson et al., 2008), and people differ a lot. Walking goes with keeping weight off, and changes in how you eat do more for losing it.

How many steps a day do I need to lose weight?

Research doesn't give a step count for weight loss. The 10,000-step figure is popular, but none of the research this article draws on tests it as a weight-loss target. In the walking programs above, people added from slightly under 2,000 to more than 4,000 steps a day. Start from your own usual day and add a little.

Can exercise boost your metabolism?

Not by much. "You can't even really boost your metabolism very much with exercise, it turns out," Pontzer says (Ologies). Over a few months the body adjusts its spending. If you add a lot of muscle you'll burn more because there's more of you, but for your size he doesn't expect much change, and he calls that understudied.

Why haven't I lost weight since I started exercising?

Exercise on its own changes weight slowly: in trials, about half a kilo for each 30 minutes a week (Jayedi et al., 2024). Keep going for the other benefits, and look to your eating habits for the bigger lever.

Should I do strength training too?

Yes, if you can. WHO advises muscle-strengthening on two or more days a week (WHO, 2020), and strength training during a weight-loss diet reduces the loss of lean mass (EASO, 2021). Bands, weights or your own body weight all work.

Sources

This article draws on Herman Pontzer's interviews on Ologies, NPR Shots and A Whole New Level, his publisher's description of Burn, Kevin Hall's interview on Guardian Science Weekly, Yoni Freedhoff's interview on Science Vs, and the studies and guidelines listed below.

• Evolutionary Anthropology (METABOLISM) with Dr. Herman Pontzer (podcast episode, official transcript, Ologies with Alie Ward, 2024)
• How Humans Really Burn Calories And What That Means For Losing Weight (interview with Herman Pontzer, NPR Shots, 2021)
• Why You Can't Exercise Your Way to Weight Loss (podcast episode with Herman Pontzer, edited write-up, A Whole New Level #293, 2026)
• Herman Pontzer, Burn (book, publisher page, 2021)
• Pontzer et al, Constrained total energy expenditure and metabolic adaptation to physical activity in adult humans (cross-sectional study, 332 adults in five countries, Current Biology, 2016)
• Jayedi et al, Aerobic exercise and weight loss in adults: a systematic review and dose-response meta-analysis (meta-analysis of 116 randomized trials, 6,880 adults with overweight or obesity, JAMA Network Open, 2024)
• Richardson et al, A meta-analysis of pedometer-based walking interventions and weight loss (meta-analysis of 9 studies, 307 adults, Annals of Family Medicine, 2008)
• Oppert et al, Exercise training in the management of overweight and obesity in adults (evidence synthesis and recommendations, European Association for the Study of Obesity, 2021)
• Donnelly et al, ACSM Position Stand: physical activity for weight loss and prevention of weight regain for adults (position stand, abstract only, American College of Sports Medicine, 2009)
• Sardeli et al, Resistance training prevents muscle loss induced by caloric restriction in obese elderly individuals (meta-analysis of 6 randomized trials in older adults, Nutrients, 2018)
• Bull et al, World Health Organization 2020 guidelines on physical activity and sedentary behaviour (guideline summary, British Journal of Sports Medicine, 2020)
• CDC, Steps for losing weight (public health page, 2025)
• The real science of weight loss, with Kevin Hall (podcast episode, Guardian Science Weekly, 2025)
• Exercise: Fat Buster or Belly Flop? (podcast episode with Yoni Freedhoff, official transcript, Science Vs, 2019)