Summary:
In adults with obesity, periodized combined training with fixed intensity significantly reduced the Visceral Adiposity Index (VAI) compared to combined training with linear intensity increase and a control group, though it was associated with no significant change in metabolic phenotype.
| PICO | Description |
|---|---|
| Population | Adults with obesity (BMI ≈33 kg/m²; mean age ≈34 years), including both metabolically healthy and unhealthy phenotypes. |
| Intervention | Periodized combined training with fixed intensity over 16 weeks targeting both aerobic and resistance components. |
| Comparison | Combined training with linear intensity increase and a non-training control group. |
| Outcome | Fixed-intensity training significantly reduced VAI (p < 0.001) in both per-protocol and intention-to-treat analyses. However, there were no statistically significant changes in metabolic phenotype classification among groups. |
Clinical Context
Obesity-related cardiometabolic risk is driven less by total body fat than by visceral adiposity, which is metabolically active and promotes insulin resistance, dyslipidaemia and inflammation. The Visceral Adiposity Index (VAI) is a surrogate measure derived from waist circumference, body mass index and lipid values that estimates visceral fat dysfunction without imaging. Patients can also be classified by metabolic phenotype, ranging from metabolically healthy to metabolically unhealthy obesity. Combined aerobic and resistance training is well established for reducing visceral fat, but how the programme is periodized — whether intensity is held fixed or progressively increased — may influence results. This trial addresses a practical gap by comparing fixed-intensity against linearly progressive combined training, and a non-training control, for their effect on VAI and metabolic phenotype.
Clinical Pearls
- Robust VAI reduction: Fixed-intensity combined training significantly reduced the Visceral Adiposity Index (p < 0.001), a strong statistical signal for improvement in estimated visceral fat.
- Consistent across analyses: The benefit held in both per-protocol and intention-to-treat analyses, increasing confidence that the effect is real rather than an artefact of dropouts.
- Fixed beat progressive: The fixed-intensity approach outperformed both the linear intensity-increase programme and the non-training control, suggesting periodization strategy matters for this outcome.
- Phenotype unchanged: Despite the VAI improvement, there were no statistically significant changes in metabolic phenotype classification among groups, indicating a limited short-term shift in overall metabolic health.
Practical Application
For adults with obesity, this trial supports prescribing a 16-week combined aerobic and resistance programme and suggests that a fixed-intensity, periodized structure may be at least as effective as — and here more effective than — continually escalating intensity for reducing estimated visceral fat. A fixed-intensity prescription can be easier to standardise, teach and sustain, which may aid adherence. Clinicians should temper expectations, however: VAI is a calculated surrogate, and the absence of any change in metabolic phenotype means improved index values did not translate into reclassified metabolic health over this period. Exercise should continue to be combined with dietary and, where appropriate, pharmacological management rather than relied upon alone to alter cardiometabolic risk.
Broader Evidence Context
The finding that combined training reduces visceral adiposity is consistent with a substantial body of evidence supporting aerobic and resistance exercise for central fat loss and cardiometabolic health. Less is known about how training periodization influences these outcomes, so the suggestion that a fixed-intensity structure outperforms linear progression is a useful, if preliminary, contribution that will need replication. The lack of change in metabolic phenotype echoes prior observations that shifting a person from metabolically unhealthy to healthy obesity is difficult and often requires larger or longer interventions, frequently alongside weight loss. Overall the results reinforce established exercise recommendations while adding nuance about how best to programme intensity.
Study Limitations
- The primary outcome, VAI, is a calculated surrogate index rather than a direct imaging measure of visceral fat.
- No significant change occurred in metabolic phenotype, limiting claims about meaningful metabolic-health improvement.
- The cohort was relatively young (mean age approximately 34 years), so results may not generalise to older adults with obesity.
- The 16-week duration and likely modest sample size limit conclusions about durability and statistical robustness for secondary outcomes.
- Adherence, diet and the precise training parameters can strongly influence such results and may constrain real-world reproducibility.
Bottom Line
In adults with obesity, a 16-week fixed-intensity combined training programme significantly reduced the Visceral Adiposity Index — outperforming progressive-intensity training and no training — but did not change metabolic phenotype. The data suggest periodization strategy can matter for visceral fat and that fixed-intensity programmes are a reasonable, adherence-friendly choice. Because the benefit was on a surrogate index without a shift in metabolic health, exercise should remain part of a broader weight and cardiometabolic management plan.
Source: Júlia Elena Fontana Ronsani, et al. “Effects of Combined Training on Visceral Adiposity Index and Metabolic Phenotype in Obesity: A Randomized Clinical Trial.” Read article here.
