The effect of sodium chloride ingestion on food intake and on fat deposition in male rats.

1. A 21 d slaughter trial was done using weanling male rats offered sodium chloride added at 10, 20 and 30 g/kg to a nutritionally adequate, control diet containing 13 g NaCl/kg, or added to the drinking-water at 5, 10 or 15 g NaCl/l. Food and drinking-water with or without NaCl were offered ad lib. and their intakes were measured. 2. NaCl in the food reduced food intake by 10-15%; NaCl in solution reduced food intake only when added at the 15 g/l level; the reduction was 25%. 3. NaCl increased the fluid intake of the rats; for NaCl in the food the increments ranged from 23 to 44%; for NaCl in the drinking-water they ranged from 44 to 229%. 4. Body fat was significantly reduced by 20 and 30 g NaCl/kg added to the control diet, indicating a reduction in the efficiency of fat synthesis. Comparable amounts of NaCl taken in the drinking-water had a negligible effect on fat deposition. 5. It is suggested that NaCl in the food produces hypodipsia, i.e. a failure to drink an optimal amount of water, causing changes in the electrolyte balance which reduce food intake and progressively reduce the efficiency of fat synthesis.