Soups increase satiety through delayed gastric emptying yet increased glycaemic response

Previous studies have demonstrated the satiating properties of soups compared with solids; however, the mechanisms controlling soup-induced satiety are unknown. This study aimed to understand the physiological mechanisms causing soup to be more satiating.

A total of 12 volunteers were tested on three occasions after a solid meal, chunky soup or smooth soup test meal for gastric emptying (GE) using the sodium [1-¹³C] acetate breath test, satiety using visual analog scales (VAS) and glycaemic response (GR) using finger prick blood samples.

There was a significant difference in GE half-time (P=0.022) and GE ascension time (P=0.018), with the longest GE times for the smooth soup and the shortest for the solid meal. The GR area under the curve was significantly different between meals (P=0.040). The smooth soup had the greatest GR (87.0 ± 49.5 mmol/l/min), followed by the chunky soup (65.4 ± 48.0 mmol/l/min), with the solid meal having the lowest GR (61.6 ± 36.8 mmol/l/min). Volunteers were fuller after the smooth soup compared with solid meal (P=0.034).

The smooth soup induced greater fullness compared with the solid meal because of a combination of delayed GE leading to feelings of gastric distension and rapid accessibility of nutrients causing a greater glycaemic response.