Consumption Of Fatty Foods Driven By Presence Of Salt.

Salt in food has been quite an issue for those trying to reduce its content and thus minimise rising levels of hypertension or blood pressure. Now it appears from two studies that a high salt intake can encourage overeating especially of fatty foods. Overeating is one of the leading causes of obesity and a major concern for many nations trying to improve the overall health of the nation. As most recognise, salt and fat are two ingredient combinations that are often found together but no attempt to understand if one impacted the other had been investigated.

The first study checked out the premise that the flavour of fat and preference for fatty foods was enhanced by levels of salt in food. Here, the research team asked 49 healthy subjects aged between 18 and 54 to taste tomato soup which had different fat contents from none at all to 20%w/w with five different salt levels from none to 2%w/w. The participants were then asked to rate the flavour, desire for the soup as well as saltiness and fattiness after they had consumed each one. To obtain a measure of their sensitivity to the fat taste, the subjects were rated on their taste for oleic acid which is a common fatty acid in many oils, when prepared at different concentrations in long-life skimmed milk.

The researchers found that salt is a major factor in the overall degree of pleasure obtained from a food, with the rating of food pleasantness varying with different salt contents. There was however no difference in food pleasantness when it came to fat concentrations of 5%, 10%, or 15%, although the fat content of 20% was rated as the least pleasant. They concluded that the strong effect of salt on pleasantness suggests that it, not fat, played a major role in the attraction of the consumers to savoury fatty foods. The conclusion from the paper suggested “that salt promotes passive overconsumption of energy in adults and that salt may override fat-mediated satiation in individuals who are sensitive to the taste of fat.”

The researchers in the second study examined the overall effect of salt on food intake. They took a similar number of subjects, 48 healthy adults also aged 18 to 54, and also established their participants’ taste sensitivity to fat. Participants were required to attend four lunchtime sessions over six-day periods. These lunches were composed of elbow macaroni with sauce, with the latter containing varying levels of fat and salt. The researchers measured subjects’ food intake over the study period and participants were required to rate the pleasantness of each food.

The researchers found that participants consumed around 11% less food and energy when their lunches contained low salt and high fat. However, when given relatively high-salt with high-fat foods, those same participants consumed significantly more food and energy. Those who were less sensitive to fat consumed the same amount in each salt condition.

The general consensus from these studies is that salt influences various physiological and biochemical responses to processes which put a brake on eating too much fat. The lead author, Russell Keast at Deakin University in Australia commented that;

 “Our body has biological mechanisms to tell us when to stop eating, and fat activates those mechanisms in people who are sensitive to the taste of fat, however when salt is added to the food, those mechanisms are blunted and people end up eating more food.”