Over the course of human evolution through hundreds of thousands of years, the body has retained a fervid biological drive to eat and to hang on to calories. This probably evolved as a protection against extended periods of going without access to food.
When you burn more calories than you have eaten, your body reacts by stimulating your appetite and delaying the message when you are satiated or full. Specifically, it releases more hunger hormone ghrelin and less of the peptides that enable the gut to signal to the brain to quit eating. This well-established concept is known as homeostasis.
But studies have shown that Western convenience diets, rich in fats and sugars, have exploited a different impulse to eat. While homeostasis is controlled by hormone signals between the gut and the brain, the separate urge to eat originates in the brain’s reward system that is also associated with addiction. Experts term this as ‘hedonic eating’, after Hedone, the Greek goddess of pleasure. Hedonic appetite is stoked by the fatty, sugary, artificially enhanced foods.
Hedonic eating has been implicated as one of the biggest reasons for obesity, as diets in many Western and other nations have become inundated with fast foods and other easy-to-partake highly processed foods that our pleasure-seeking brains compel us to eat.
In particular, sweet foods flood the brain with the chemical signal dopamine. Once triggered, people may seek them out over and over again for the jolt of pleasure they bring. Under this theory, a hankering for doughnuts could be as hard-wired as a craving for heroin or alcohol.
But, just as our body does not require addictive substances, they do no not need the extra calories in fast foods. Doctors say that the obesity epidemic has nothing to do with the need for calories. It has everything to do with wanting more food and the pleasure from certain foods, while the calories are just along for the ride.
And those tasty triggers are everywhere. Ultra-processed foods such as soft drinks and fruit drinks, breads, breakfast cereals, chips, and frozen pizzas make up almost 60 percent of many Western daily calories. These foods are combinations of sugar, salt, fats, artificial flavoring, color, and texture — precisely calibrated industrial recipe for temptation.
And, once you gain those kilos, any attempts to shed them usually backfire. Health experts estimate that for every kilo drop in weight your waistline gets saddled with 130 more calories a day. Drop 5 kilos and your body is likely to prompt you to eat 650 more calories a day.
Your body claws back the lost weight by slowing your resting energy burn so you need fewer calories while it also ramps up hunger hormones and turns down hormones that make us feel full. The net result is that you want to eat more than before you slimmed down.
While homeostatic hunger has a built-in cue to stop, hedonic eating is harder to control as there is no off-switch when we have had more than we need. Researchers at Drexel University in the US, studying why some people stop after a few bites of a treat while others keep on eating, say it could be a mixture of our genes, environment, and whether the brakes in our brain, the inhibitory response that helps us resist impulsive behavior, is sufficiently strong.
The researchers have developed a new technique, called Inhibitory Control Training, to help people overcome eating just for pleasure. The training is based on the ‘dual-process model of self-control’. The idea is that everyone has an impulsive side that gives into rewarding temptations, but we also have a rational side of our brains that can stop those impulses to align our behavior with our goals.
The training aims to strengthen the rational thought process so that you reach for that stalk of broccoli instead of a bag of pretzels.To study its impact, researchers recruited people who said they ate sugary foods at least three times a day. They divided the study participants into two main groups. One group received inhibitory control training, while the other went through a sham exercise. Everyone then went on a no-sugar diet. They completed their training every day at home.
By the end of the study, the two groups showed little differences in weight loss. But when researchers parsed the data more closely, they found that the training paid off the most for people whose cravings for sweets were the strongest. After 8 weeks of inhibitory control training, those who were the most intensely tempted by sugar lost about 50 percent more weight than their counterparts in the placebo group.
The researchers admit that their technique is not yet ready for roll-out to the wider public, but it nevertheless provides proof of principle that hedonic hunger can be controlled.