|Think you cannot eat the whole pizza? Add salt - this should "help" with the hardest all-you-can-eat challenges.|
The fat to carbohydrate ratio Hoch et al. identified as a crucial determinant of snack food intake and brain reward responses in their 2015 study is yet not the only characteristic feature of potato chips.
Another similarly striking feature chips share with a couple of other highly addictive foods is their salt content. The same salt content of which Bolhuis et al. write in their soon-to-be-published paper in The Journal of Nutrition that we don't know yet how it interacts with the appetitive effects of fat. Apropos fat, whether fat will increase or decrease your appetite is actually highly individual question. Some studies even suggest that a high fat content has appetite reducing effects - at least in those individuals with a high fat taste sensitivity.
Unfortunately, the results of pertinent studies are inconclusive; and that even in people with intact fat taste sensitivity. In view of previous research showing similar associations between the salt content of snack foods and their appetizing effects as they were observed for high carbohydrate + high fat foosds, Bolhuis et al. speculated that our fat taste sensitivity may be influenced by the co-ingestion of salt. To test this hypothesis, the researchers recruited forty-eight healthy adults [16 men and 32 women, aged 18–54 y, body mass index (kg/m2): 17.8–34.4]. After an initial assessment of their individual fat taste sensitivity, the subjects participated in a randomized 2 x 2 crossover design trial, in which each participant attended 4 lunchtime sessions after a standardized breakfast.
|Figure 1: The high salt meals were generally rated as more pleasant, while fat had no effect on the perceived pleasantness of the meal (Bolhuis. 2016).|
- low-fat (0.02% fat, wt:wt)/low-salt (0.06% NaCl, wt:wt),
- low-fat/high-salt (0.5% NaCl, wt:wt),
- high-fat (34% fat, wt:/wt)/low-salt, or
The results indicate that salt increased food (= food weight) intakes by 11%, independent of fat concentration (P = 0.022), while increasing the fat intake had no independent effect of fat on food intake (P = 0.6 for the amount of food, not its energy content).
|Figure 2: This is what really counts, the effects of modfiying fat and salt content of the meals on total energy intake during the meals; data in kcal per meal (Bolhuis. 2016).|
|Figure 3: When the diet was high in salt, the mediating effect of fat taste sensitivity on food intake (in g) is lost (Bolhuis. 2016)|
More importantly, however, the fat taste sensitivity appeared to decrease signifi-cantly with increasing amounts of salt in the high-fat meals (fat taste x salt interaction on delta intake of high-fat - low-fat meals; P = 0.012), which tended to trigger a satiety effect in the fat sensitive subjects only if they were also low in salt (see Figure 3).
- Bolhuis, Dieuwerke P. et al. "Salt Promotes Passive Overconsumption of Dietary Fat in Humans." The Journal of Nutrition (2016): Ahead of print.
- Hoch, Tobias, et al. "Fat/carbohydrate ratio but not energy density determines snack food intake and activates brain reward areas." Scientific reports 5 (2015).