Mostly no. In most trials, training a body part did not remove more fat from that part: six weeks of ab exercises left belly fat unchanged2, and training one leg took fat from the arms and trunk, not the leg3. One small newer trial did find a little extra trunk-fat loss with a specific ab endurance programme, which is why "mostly" is the honest word4.
Spot reduction means losing fat from the area you exercise because you exercise it. Below is what the trials tested and why the newest one is interesting but not a reversal.
Why the idea is appealing
Working muscles use fat as fuel, and some belly fat sits right over the ab muscles. It feels logical that crunches would draw on the fat closest to them.
The catch is how fat is released. Stored fat is broken down and carried in the blood to wherever it is used, so a working muscle can draw on fat from anywhere in the body. The 2023 authors describe the mainstream view this way: exercise-induced fat release happens "predominantly through whole-body fat release, rather than from local adipose tissue storages adjacent to the working muscles"4. The trials below test that directly.
What the trials tested
The clean design is to train one area and measure fat in that area against an untrained one, or against a group that did not do the local work.
| Trial | Who | What was trained | How long | How fat was measured |
|---|---|---|---|---|
| Kostek 2007 | 104 adults | non-dominant arm only | 12 weeks | MRI and skinfolds, both arms |
| Vispute 2011 | 24 sedentary adults | 7 ab exercises, 2 × 10, 5 days a week | 6 weeks | DXA, tape, skinfolds |
| Ramírez-Campillo 2013 | 11 young adults | one leg, very high-rep leg press | 12 weeks | DXA by region |
| Brobakken 2023 | 16 men with overweight | ab endurance work plus treadmill vs treadmill only | 10 weeks | DXA by region, blinded technician |
DXA is a low-dose X-ray scan that measures fat and lean mass in each body region. MRI images tissue directly.
What the trials found
Ab exercises alone, six weeks. Twenty-four healthy, sedentary adults aged 18 to 40 were randomised to ab training or no training, and everyone kept their food intake steady2. The ab group did 7 exercises, 2 sets of 10, five days a week. There was no significant effect on body weight, body fat percentage, fat in the belly region, waist size, or skinfolds over the belly. The ab group did get stronger at the task: 47 curl-ups on the final test against 32 in the control group.
One trained leg, twelve weeks. Eleven young adults trained only their non-dominant leg, with 960 to 1,200 reps of light leg press per session, three times a week3. Whole-body fat mass fell by 5.1%. But fat did not change significantly in the trained leg. It fell in the arms (10.2%) and the trunk (6.9%), and the drop there was significantly larger than in the trained leg.
One trained arm, twelve weeks. In 104 adults who trained only their non-dominant arm, MRI found no difference in fat change between the trained and untrained arms1. A skinfold pinch over the trained muscle did show a local drop in men, but not in women or the whole sample; the authors judged MRI the better measure and concluded it supports "the notion that spot reduction does not occur".
In plain terms: three trials, three body parts, and in each the fat that came off did not come preferentially from the part being trained.
The newer trial that disagrees
A 2023 trial set out to test spot reduction more strictly than before4. Sixteen men with overweight, aged about 43, were randomised to two programmes, four days a week for 10 weeks:
- Ab group: 27 minutes of treadmill running plus four 4-minute bouts of torso-rotation and crunch machine work at 30 to 40% of their one-rep max.
- Treadmill group: 45 minutes of treadmill running.
The key design choice: the sessions were matched for total energy used, measured by oxygen uptake. So any difference in where fat came from should be about location, not effort.
Trunk fat fell more in the ab group, by 697 g more than the treadmill group (about 3%). In the ab group it fell about 1.2 kg (7%); in the treadmill group it did not change significantly4. Everything else moved alike: total fat fell in both groups with no difference between them, waist size fell by 5 cm in both, and leg fat fell in both by the same amount.
Trunk fat before and after 10 weeks, ab work vs treadmill only · kg
Before After 10 weeks
The authors concluded that "spot reduction exists in overweight adult males"4.
How to read the disagreement
It is one small trial against several, and the details matter:
- Eight men per group. Small trials can find differences that do not repeat.
- The ab group started with more trunk fat (about 16.3 against 12.2 kg), which the authors did not find statistically different but acknowledge could have mattered4.
- The waist did not know. Waist size fell by the same 5 cm in both groups, and total fat loss was the same. A difference that shows up on a regional scan but not on the tape is small in practice.
- The sessions were long. Matching energy made the ab group's sessions 84 minutes, almost double the treadmill group's.
- Men only, and the scan could not tell belly fat under the skin from fat around the organs.
So the fair summary is not "spot reduction is a myth" or "spot reduction works". It is: in most trials there was no local effect, and the one trial that found one saw a small effect with the same total result.
In plain terms: crunches build the muscle under the fat; the fat mostly comes off wherever the body takes it from.
What does lower belly fat in trials
Whole-body exercise does. A 2025 meta-analysis pooled 12 randomised trials (591 adults with overweight or obesity) that measured belly fat with scans against no-exercise controls5. Visceral fat area, the fat around the organs, fell by about 7.1% and subcutaneous belly fat, the fat under the skin, by about 9.1%. Higher-intensity exercise was linked to larger drops.
Change in belly fat area with exercise vs no exercise, 12 trials · %
Energy balance over time sets total fat (see calories in, calories out), and training type changes how much comes from lean or fat mass (covered in our article on cardio or weights for fat loss). Tracking the change is easier with a tape than a mirror; how to take body measurements covers the method.
What the studies found
| Study | Who was studied | Key result | Year |
|---|---|---|---|
| Kostek et al., *Med Sci Sports Exerc*1 | 104 adults, one arm trained 12 weeks | MRI: fat change the same in trained and untrained arm | 2007 |
| Vispute et al., *J Strength Cond Res*2 | 24 sedentary adults, ab exercises 6 weeks vs none | No significant change in any belly-fat measure | 2011 |
| Ramírez-Campillo et al., *J Strength Cond Res*3 | 11 young adults, one leg trained 12 weeks | Whole-body fat −5.1%; not in the trained leg; arms −10.2%, trunk −6.9% | 2013 |
| Brobakken et al., *Physiol Rep*4 | 16 men with overweight, ab endurance vs treadmill, energy-matched, 10 weeks | Trunk fat 697 g more lost with ab work; same total fat and waist change | 2023 |
| Igarashi et al., *Obes Res Clin Pract*5 | 12 RCTs, 591 adults with overweight or obesity | Exercise vs none: visceral fat −7.1%, subcutaneous belly fat −9.1% | 2025 |
Limits worth knowing
- Every trial is small except the 104-person arm study, and none lasted more than 12 weeks.
- Different measures. Skinfolds, tape, DXA and MRI do not always agree; the arm study showed a skinfold effect in men that MRI did not confirm1.
- Abstract only for the 2007, 2011, 2013 and 2025 papers. We read the 2023 trial in full; it reports no funding.
- No meta-analysis of spot reduction itself turned up in our searches.
- Diet was not controlled in the 2023 trial; participants were asked not to change their eating.
Latest research
The newest study we opened is the 2025 meta-analysis of whole-body exercise and belly fat5: across 12 trials, exercise without any local focus lowered both visceral and subcutaneous belly fat against no exercise, more so at higher intensity. The newest trial of spot reduction itself is the 2023 energy-matched study above4. Until it is repeated in larger groups and in women, it is a reason to say "mostly no" rather than "no".
The short version
- In most trials, training one area did not take more fat from that area.
- Six weeks of ab exercises left belly fat unchanged but built ab endurance.
- One small 2023 trial found a little extra trunk-fat loss with ab work, with the same total fat and waist change.
- Whole-body exercise lowered belly fat in a 2025 pooled analysis of 12 trials.
Educational overview only — not medical advice.
