Benefits
Satiety support (proposed, not confirmed in the cited trial)
Increased fullness and reduced intake at a later meal is the intended effect of this emulsion, but it is not demonstrated by the evidence cited here: the one randomized crossover trial on this page (Chan 2017, 18 lean men) tested the commercial product and found no change in short-term appetite or food intake. Earlier reports of reduced later-meal intake have not been consistently reproduced.
Appetite management
Extending the time between meals and curbing snacking is how Fabuless is marketed, not an outcome demonstrated by the evidence on this page. In the randomized crossover trial cited here, the commercial emulsion did not change short-term appetite or the amount eaten at the next meal.
Honest evidence note
Results across trials are mixed: several studies found no significant effect on appetite or weight, so benefits should be viewed with realistic expectations.
Mechanism of action
Ileal brake activation
The proposed mechanism is that the emulsion delivers fat to the lower small intestine intact and engages the ileal brake, a reflex that slows digestion and contributes to fullness. This is the design rationale for the product; in the human trial cited here it did not translate into a measurable appetite or food-intake effect.
Delayed fat digestion
Slower release of fatty acids is hypothesized to prolong satiety signaling from the gut to the brain. This remains a proposed mechanism and is not supported by an appetite or intake benefit in the trial cited on this page.
Clinical trials
Six-arm randomized crossover study of small particle size lipid emulsions, including the commercial Fabuless product, on acute satiety and energy intake in 18 lean men. (Chan et al. 2017, Physiology and Behavior)
18 lean men (small acute-feeding crossover; results may not apply to people with overweight or obesity).
This trial was null: the authors reported no evidence that the small particle size dairy lipid emulsions or the commercial Fabuless product altered short-term appetite or food intake in lean adults. It was a six-arm randomized crossover in 18 lean men, so it speaks to acute appetite only; across the wider literature, appetite and weight results have been mixed.