The categories answer different questions: weight management supplements use fibers, stimulants, botanicals, minerals, or multi-ingredient blends marketed to affect appetite, energy expenditure, absorption, or body weight; gut health supplements deliver strains fibers enzymes or other ingredients aimed at a defined digestive function.
The decision depends on different mechanisms. For weight management supplements, examine active ingredient and stimulant load; for gut health supplements, examine strain identity and viable count. Features should enter the decision after the use case is specific.