The Claim

In recreationally trained runners, wearing a 10% body weight vest during running at 70% and 75% of VO2max reduces fatty acid oxidation by approximately 10% compared to running without a vest, due to increased exercise intensity shifting substrate utilization toward carbohydrates rather than fat.

Source: Predictors of Fat Oxidation and Caloric Expenditure With and Without Weighted Vest Running

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
55score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Cause and effect
1 study reviewed
In plain English

When recreationally trained runners wear a vest that adds 10% of their body weight and run at 70% to 75% of their maximum oxygen uptake, their bodies burn 10% less fat than when they run without the vest, because higher intensity shifts energy use from fat to carbohydrates.

See the scientific wording

In recreationally trained runners, wearing a 10% body weight vest during running at 70% and 75% of VO2max significantly reduces fatty acid oxidation by approximately 10% compared to running without a vest, likely due to increased exercise intensity shifting substrate utilization toward carbohydrates rather than fat.

Why this might work

Carrying extra weight while running forces the body to work harder, which increases the need for quick energy. This causes muscles to rely more on sugar instead of fat for fuel because sugar can be broken down faster to meet the higher demand.

Supported mechanismbased on 1 study

What the research says

1 study
  1. Study: Predictors of Fat Oxidation and Caloric Expenditure With and Without Weighted Vest Running

    When runners wear a backpack that’s 10% of their body weight and run pretty hard, their bodies burn about 10% less fat and use more carbs for energy, because the extra weight makes the workout harder. The study proved this happens.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.