According to a new book — Salt, Sugar, Fat: How The Food Giants Hooked Us — the food industry has spent years mixing these three ingredients, salt, sugar and fat in an ideal combination to make crisps addictive.

Michael Moss, an award-winning investigative writer, who works at The New York Times, spent more than three years gathering information and interviewed food industry insiders to find out how and why manufacturers make products that could damage people’s health.

The author says that producers describe the levels of salt, sugar and fat in processed food that are so attractive they make us to want more as a “bliss point,” a perfect link between food and joy in consumers’ brains. Studies show that the “bliss point” for children can be 36 per cent sugar content in food, three times that of most adults.

Thousands of customers’ preferences are scientifically tested, and surveys are conducted in populations for cultural and demographic differences. MRI-scanning studies are used to investigate the sensory power of food (how sugar lights up the brain the same way it does after someone has taken cocaine, for example).

“We’re not born liking salt. It doesn’t happen until we’re six months old. So, it looks like the processed food industry is controlling our cravings. And studies show that kids who are fed processed food from a very young age develop huge salt cravings,” says the author.

“Monosodium glutamate — an additive used to create the fifth taste, umami, which enhances our overall perception of a food — is also found in many crisps. The use of this additive in crisps, alongside salt and other flavor enhancers, is a stimulant for the taste buds, which makes us crave more of them. The concept that crisps are addictive is not yet proven but there are ongoing studies to look at whether overeating the sugars that form the carbohydrates in crisps triggers some of the neuronal pathways in the brain that have been associated with addiction,” says Ella Boger, a dietitian at Chelsea and Westminster Hospital.

Asides from being potentially addictive, crisps can be dangerous to the teeth, Dr Nigel Carter, chief executive of the British Dental Health Foundation, says.

According to Dr. Carter, crisps are not an obvious danger to oral health as they do not contain the same amount of sugar as chocolate bars and sweets. However, they can actually be even more problematic because they tend to stick to the surfaces of the teeth and can remain there for several hours. Dr Carter also said that eating crisps could potentially be harmful because people tend to look at labels for sugar content and ignore the carbohydrate content, which is broken down by the body into sugar. To promote good oral health you need to brush your teeth twice a day and avoid snacking on sugary or starchy foods between meals, he said.

Salt, sugar, and fat are the key ingredients, according to Michael Moss.

Producers have found it is cheaper to make salt, sugar and fat more alluring by modifying their chemical structure rather than make the product healthy. Moss persuaded three of the biggest food manufacturers to make him samples of their products with significantly reduced levels of the three ingredients.

“Without any salt, the crackers lost their magic,” says the author.

The same happened with soups, meats and breads.

“Take more than a little salt, or sugar, or fat out of processed food, these experiments showed, and there is nothing left. Or, even worse, what is left are the inexorable consequences of food processing; repulsive tastes that are bitter, metallic and astringent,” says Moss.

“The food industry prefers not to speak of ‘addiction’ or ‘addictive’. ‘Crave-able’ is the acceptable term,” he says.

When producers have to reduce one of their three key ingredients, they often raise the levels of the other two, Moss says, to maintain their attractiveness. Products labeled “low salt” may have higher levels of fat and sugar.

“It is one of the industry’s most devious moves. That is why we should all be very wary of products whose labels proclaim: ‘Now low in. . . ,” says Michael Moss.

Food scientists have developed enhancers to boost sugar’s sweetness up to 200 times, and one component, fructose, has been crystallized into an additive to boost the allure of foods naturally low in it.

The body does not process fructose syrup in the same way as natural sugar. The liver is overburdened, and that leads to raised levels of fat in the bloodstream, and cardiovascular disease. Over-consumption of salt has been linked with high blood pressure and heart disease. Excessive intake of fat is linked with obesity and related epidemics, diabetes, stroke.

“Recent scientific reviews show there is no evidence to suggest food addiction exists in people, either to specific foods or to nutrients like sugar or fat. There is also no convincing evidence to show that people who are overweight display signs of addiction,” says Barbara Gallani, director of food safety, science and health at the Food and Drink Federation in the UK.

According to Moss, in the U.S. eleven heads of the largest food companies met in secret in 1999 to discuss how to reduce the emerging obesity epidemic by changing recipes and strategies, but no constructive action followed.

More over, most of the executives at the big food companies do not consume their own products, they prefer to eat fresh foods and take regular exercise, says Moss.

“I found that many of the executives I talked to go out of their way to avoid their own products, especially if they have run into health problems,” he says.