Intermittent fasting: The diet to watch in 2018?

17 Jan 2018 --- With rates of obesity continuing to skyrocket, the weight loss market is seeing persistent growth, experiencing an explosion in sales especially around the New Year. In this space, intermittent fasting (IF) is becoming increasingly popular, with organizations such as Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) touting its benefits. IF is an umbrella term encompassing a range of diets where the pattern of calorie restriction and timing of food intake are altered so that individuals undergo frequently repeated periods of fasting or modified fasting (allowing a low calorie intake of approximately 500-600 calories per day). What is the science behind this range of diets, and what sort of opportunities do they offer the food industry?

In general, most science-based diets build in a form of calorie-restriction and/or focus on macronutrient distribution. “The latest diets and trends that are growing quickly are based upon variations of Intermittent Fasting (IF),” says Dr. Rona Antoni, Registered Dietitian and Research Fellow in Nutrition Metabolism at the University of Surrey.

“These are highly popular today. Proponents of IF claim that it can improve blood sugar levels, decrease the risk of heart disease, stroke and cancer, prevent or delay the onset of neurodegenerative diseases and even improve memory, mood and depression,” adds Dr. Roy McGroarty, an Infectious Disease Specialist and Humanitarian relief, recovery and development Program Manager. 

Popular examples of diets based on IF include the 5:2 diet and alternate day fasting. In May, CSIRO launched a new “flexi” diet that includes intermittent fasting three days a week. The weight loss program is based on research carried out by CSIRO scientists who found that fasting can be an effective way to lose weight and stay healthy.

According to the organization, participants in the 16 week trial lost an average of 11kg and saw improvements in cholesterol, insulin, glucose and blood pressure.

“This was the largest study exploring the effects of an intermittent fasting style of diet on weight loss, health and nutrient status,” says CSIRO Research Dietitian Dr. Jane Bowen. “In addition to improvement in weight loss and overall health, we also observed psychological improvements, with participants indicating better control over eating habits.”

The reason that fasting can have a positive effect on harmful processes in the body is that during all kinds of fasting periods, various biochemical and molecular changes take place in the body. These include an increase in certain protective proteins, antioxidant enzymes, vitamin E and coenzyme Q10; all of which have a protective effect and prevent inflammation and oxidative stress.

“The idea behind the IF diet is threefold: The first is glycogen depletion as a result of fasting,” explains Dr. Samefko Ludidi, food researcher at the Gastronomy Research Center of the Hotel Management School Maastricht. “Depending on your level of physical activity glycogen stores are depleted after a period of about 8-12 hours fast. Second, following glycogen depletion, the body starts utilizing fat stores as an energy source. Third, fasting results in an average energy deficiency compared to the normal situation. The combination of these three aspects could result in weight loss.”

“There are some suggestions that this dieting approach may result in greater improvements in some markers of insulin sensitivity,” Antoni says.

“New insights revealed that people with diabetes mellitus Type 2 might even benefit from an IF way of eating,” Ludidi adds. 

Anyone who eats according to intermittent fasting becomes more sensitive to insulin, which increases the growth hormone production again. Scientists have known for years that there is a strong link between insulin sensitivity and growth hormone production, because increased insulin resistance results in a decrease in growth hormone production. Intermittent fasting is good for cholesterol and triglyceride levels. Studies have shown that the ratio between the LDL level (the “bad cholesterol”) and the HDL level improves with intermittent fasting. 

One drawback of IF is that the initial transition is quite difficult. How difficult depends on the individual, as the body only requires 1-2 weeks to adjust to the new eating schedule. 

Some argue that you could eat anything when on an IF diet, as long as you stay in the negative energy balance. “But it is not only about calories. You cannot expect to lose weight healthily by getting that energy deficit from drinking a bottle of soda each day,” stresses Ludidi. 

McGroarty adds: “The food industry can, therefore, help by lowering the production of highly processed foods, agreeing to better nutrition labeling and by stopping the ‘Bliss Point’ food testing method. In almost every case it involves adding sugar far beyond what the body requires.” Antoni concludes: “The modern-day food environment makes sustainable, healthy eating behaviors difficult. The industry has the responsibility to do their bit and make it easier for the consumers.”

A detailed version of this article, “Intermittent Fasting: A New Year's Resolution” by Maartje Geraedts, will appear in the February issue of The World of Food Ingredients.