Weighted Vests Cause Weight Loss - But Not for the Reason You Think

You may be able to trick your body into losing weight with a weighted vest. Remarkable research is showing how strategically mechanically loading your body can toggle your brain to decrease hunger.

Since a version of this post is now freely available in full at Michael Easter’s amazing newsletter (Two Percent) as a guest post, I’ve made it free here as well. To those who are new—welcome! I’m so glad you’re here. Here's a quick intro about me and what you can expect if you choose to subscribe and learn with us.

Brief Bio: I earned my PhD in Human Metabolism from Oxford, then completed my MD at Harvard. Along the way, I became deeply passionate about teaching nutrition and metabolism—because there’s truly nothing more empowering than helping people gain deep knowledge and sparking real curiosity to learn more.

What you can expect: I promise nuance, the occasional broken expectation, and a whole lot of engaging, evidence-based science.

If you liked this post, you might also enjoy: Untangling the Seed Oil Debate, Why Vitamin C Is the Most Underrated Nutrient for Heart Health, The Sugar Diet Works—But Not for the Reason You Think, How Heart Disease Causes Brain Damage, The Real Root Cause of Autoimmune Disease

And, coming later this month: Dogs as Medicine, Fighting Visceral Fat in Middle Age, How Exercise Molecularly Reprograms the Heart, and more.

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Weighted Vests Cause Weight Loss - But Not for the Reason You Think

Humor me for a moment and imagine you’re gaining too much weight for your skeleton to handle. Your bones – cranky that your dietary excursions are forcing them to work extra hard against gravity – respond by sending a signal to your brain that says, “Hey, you’re getting too heavy. Cool it the snacking!” Remarkably, your brain responds by decreasing your appetite.

And while this may sound like science fiction – but there is metabolism in the madness.

You may be able to trick your body into losing weight with a weighted vest. Remarkable research is showing how strategically mechanically loading your body can toggle your brain to decrease hunger.

We’ll break it all down, and you’ll leave with practical tips, and just might end up wearing your groceries more and eating them less.

Roadmap: Three Studies… Building Suspense

In this letter, I want to walk through three studies. The first two are human randomized controlled trials (RCTs) and the third is an animal model study. We’re going to blaze through the human studies because, while they establish the human relevance of these findings, they merely set the stage for the remarkable mechanistic findings. You’ll see what I mean when we get there. But first… people.

Human RCT 1: Short-Term, Big Impact

In one RCT, 72 participants with obesity were randomized to wear a weighted vest (11% body weight) or a non-weighted vest (1% body weight) eight hours per day for three weeks. For a 70 kg person, that amounts to a 7.7 kg (16.9 lb) weighted vest.

The study found that randomization to wear the weighted vest resulted in statistically significant weight loss over just three weeks (1.61 kg). Furthermore, all of this weight loss was fat loss (-1.73 kg), with a +0.20 kg change in lean mass. Even for people with obesity, losing fat without losing (or maybe even gaining?) muscle over a short time period is impressive.

But this study was just three weeks. What happens if one were to wear a weighted vest for much longer?

Human RCT 2: Long-Term Weight Loss Defense

In another 2025 RCT, participants were randomized to wear a weighted vest (~6 kg for 6.6 hours per day) for six months or to a control group. But this study came with two additional features.

• First, during this six-month phase, both groups were placed on a strict, very low-calorie diet (1,100–1,300 Calories).

• Second, all participants were then followed for an additional 18 months after the intervention ended. In other words, for 0–6 months people ate a very low-calorie diet with or without wearing a weighted vest; and then for 6–24 months people were left to live their lives freely without the weighted vest or a diet.

Both groups lost the same amount of weight during the initial six-month intervention, likely owing to the very restrictive nature of the diet. But what happened next was fascinating… while the control group gained all their weight back, the weighted vest group only gained half the weight back.

In other words, weight regain was twice as much in the control group as compared to the weighted vest group after the intervention ended.

This suggests there was a ‘lingering’ metabolic effect of wearing the weighted vest. Weird? How? What’s going on?

Before I reveal the possible mechanism, try to generate your own hypothesis and – if you’re bold – share it in the comments.

Now… let’s reveal the metabolic secret…

Lab Rats, Loaded Vests, and a Weighty Discovery

The animal study I’m about to break down was actually the basis for the first human trial we discussed. It was published by the same research group who, in 2018, developed the hypothesis of a “gravitostat” – a weight sensor in your body that regulates fat mass.

In this ingenious study, they loaded mice and rats with capsules equal to 15% of their body weight, the rodent equivalent of a weighted vest (so I’m just going to refer to weigh-loaded animals as the ‘weighted vest’ group).

Remarkably, compared to control animals that were loaded with empty capsules, the ‘weighted vest’ animals lost a tremendous amount of weight over just two weeks.

And, interestingly, the ‘weighted vest’ animals lost about as much weight as the additional load they were forced to carry.

Gravity Up, Forks Down

Now, if we were thinking superficially about the weight-loss mechanism behind wearing a weighted vest, we might assume you just burn more calories. Along with increased energy expenditure, we might hypothesize appetite would increase or ‘at best’ remain the same.

But that’s NOT what the researchers observed.

Instead, weight loss was explained by a large decrease in food intake in the ‘weighted vest’ animals. In fact, when control animals were force-fed a restricted diet to match the intake of ‘weighted vest’ animals, they both lost the same amount of weight.

Pause and consider this: Increasing the gravitational load on these animals decreased their appetite; their bodies appeared to respond by adjusting food intake until their total weight with the weighted capsules was equal to their starting weight without the weighted capsules.

This was the origin of the “gravitostat” hypothesis — the idea that the body, particularly the bones, senses an increased gravitational load and sends signals to the brain to curb food intake. The goal? To bring the organism (whether that’s Stuart ‘Not So’ Little or future you after an all-inclusive Disney cruise) back to a movement-friendly body mass.

A Conserved Mechanism: From Mammals to Birds

Before we dive into the mechanism, it’s worth highlighting that this phenomenon appears to be conserved across species. We've already observed similar responses in humans and rodents — but does this system extend beyond mammals?

Birds are a logical next group to investigate. After all, if a bird gets too heavy, it quite literally goes the way of the dodo. (Though, as everyone knows, the real culprit behind the dodo’s extinction was a tragic melon deficiency caused by an obnoxious sloth.)

Anyway — yes indeedy do-do — when researchers attached small weights to the backs of homing pigeons, equal to roughly 5% of their body weight, the pigeons compensated by losing nearly the same amount of body mass. When the load was removed, the birds regained the lost weight (blue), and vice versa (orange). By adding or removing the weights, the researchers could toggle the pigeons’ body weight almost as easily as flicking a switch.

These findings suggest that the gravitostat may be a deeply rooted, evolutionarily conserved system — one that helps animals, feathered or otherwise, maintain their optimal size.

Not the Usual Suspects: Leptin, GLP-1 and other Weight Regulatory Hormones

Now, back to rats and mice. In an effort to figure out the mechanism, the researchers went about doing what researchers do: they tinkered with different hormone systems to figure out what might be mediating the weight-loss and appetite-curbing effects of the mechanical loading.

Was it the appetite-regulating hormone leptin? Nope.

When the same experiment was performed on leptin-deficient (Ob/Ob) mice, the results were the same. This suggests the mechanism was independent of leptin.

What about the weight-loss hormone GLP-1? Nope. It wasn’t GLP-1 either.

What about ghrelin? αMSH? ERα? Sclerostin? FGF-23? Osteocalcin? Lipocalin?
Nope. Nope. Nope. Nope. Nope. Nope. Nope.

Then, the researchers found it!

Your Bones Speak Up: “Put Down that Donut!”

When they knocked out the function of osteocytes – cells in bones that sense mechanical load and coordinate bone remodeling – the weight-loss effect was completely abolished. You don’t need a fancy degree to see that in the graph below.

• Left, Normal response: Adding a load leads to weight loss.

• Right, No Response: In animals without functional osteocytes in bone, adding a load does ‘diddly squat’ to for weight loss. (Sorry for the highly technical scientific term.)

So, let’s return to our initial scene. Your bones, upset they need to carry extra load, signal to your brain to curb your appetite. It doesn’t sound like science fiction anymore, does it?

“Leptin at the Bottom & Gravity Up Top” - Building a Model of Weight Homeostasis

Before we dive into practical ways to apply this science, let’s zoom out and connect the dots between the “gravitostat” and what we already know about weight regulation — especially the role of the hormone leptin.

First, consider that each of us has a natural range of comfortable body weights. Sure, weight fluctuates from day to day and week to week, but most of us hover within a familiar zone.

From an evolutionary perspective, this makes perfect sense. Small shifts in weight don’t threaten survival.

• But if your weight drops too low, it signals starvation and frailty.

• Too high, and mobility and agility suffer.

It follows that our bodies have built-in mechanisms designed to nudge us back into that healthy range.

One of those mechanisms is leptin — a hormone released by fat tissue. When fat stores dip too low, leptin levels fall. This drop signals the brain to conserve energy and ramp up food seeking, helping to restore lost weight. You can think of leptin as the “bottom guardrail,” pushing weight back up when it falls too low (blue).

At the opposite end of the spectrum, the gravitostat comes into play. This system senses increased body weight — essentially, increased loading on the skeleton — and works to push weight back down when it creeps too high. In other words, gravity acts as the “top guardrail” (purple).

Interestingly, these two systems appear to complement each other. The body’s response to leptin is strongest in leaner organism, while the gravitostat’s weight-reducing effect becomes more pronounced in those with obesity.

Of course, it’s not quite that simple. Factors like central leptin resistance and other hormonal signals can shift your weight set point or make it harder to return to your natural range. Still, this “dual mechanism” model — with leptin at the bottom and gravity at the top — offers a powerful lens through which to understand how biology works to keep your weight within optimal boundaries.

Putting the Gravitostat to Work

Now, here’s how you can apply this research in your own life:

• Consider a weighted vest: Start light — around 5–10% of your body weight — and wear it for short periods during daily tasks like walking, working, or chores. Gradually build up to longer durations and/or greater weights as tolerated. For safety, keep it below 30% of body weight.

• Focus on consistency, not discomfort: This isn’t about extreme workouts. It's about subtle, consistent mechanical loading throughout the day.

• Incorporate mechanical loading into your life: At the grocery store, rather than grabbing a pushcart, grab a hand basket. Little swaps like these can accumulate to build your biceps, bones and – like I said in the opening – “you might end up wearing your groceries more and eating them less.”

  *Also, it is written in section 4.2 of the official Bro Code Manual that carrying four grocery bags in one hand affords +6 Testosterone points. True fact.

• Become an Airport Walker: Find yourself at the airport with a layover and a carry-on bag? You could sit a lounge. Or, you could pick up your bag, turn on a podcast, and carry it around for a couple of miles while waiting for your flight. (Credit for this idea goes to Michael Easter on the Daily Stoic Podcast)

• Pair it with healthy habits: A weighted vest isn’t magic, but it may complement good nutrition and regular activity by naturally reducing your appetite.

The bottom line? Sometimes the fastest way to shed pounds is to strap them on first.