Why does sugar continues to be tasty, irresistible but yet unsatisfying?
Fructose paired with glucose in both table sugar and high-fructose corn syrup is a fixture in diets worldwide. Increasingly the factor to blame for epidemics of obesity, diabetes and a wealth of related health problems. Scientists are still struggling to understand both the complicated metabolic effects and secrets of the allure: why we’re so drawn to consume sugar in sodas, desserts, snacks.
Why we’re drawn to it?
Deals with complicated relationships and correlations between diet, subjective perceptions, behavior. Sweetness itself is a primordial motivational signal and gratifying for the brain, signals we’ve eaten something good and should eat more. This signal gets knocked out of whack when sugar is consumed in excess.
Fructose is far sweeter than glucose. Two recent studies show how fructose manages to be tastier and more alluring than glucose but still remain less satisfying
- Study 1: Scientists at USC
- Study 2: researchers at University of Basel, Switzerland
- Examined how participants responded to liquids sweetened with glucose and fructose
- Brain scans, questionnaires about feelings of hunger and fullness and had blood test for hormones that regulate appetite
- Each study shows glucose and fructose had very different effects on hormonal effects and brain activity
- Volunteers in the Basel study felt fuller and less hungry on the glucose solution than the fructose
- Had higher levels of appetite-suppressing hormones
- Several brain regions associated with gratification were more active with glucose
- Fructose: signals stop eating and drinking were absent
- Fructose tends to yield pleasure but little satisfaction
- USC Study:
- Examined different angles
- Flashed photos of pizza and other high-calorie foods in front of subjects after they consumed sugar
- Asked if they’d like to eat it right away or wait a month for money
- Fructose: people wanted to trade away the money and eat it right away
Both studies showed fructose increasing brain activity in the orbitofrontal cortex (area involved in integrating sensations, rating the pleasure or displeasure of foods, and weaving those things into conscious decision-making.
Helps explain fructose can be nutritionally marginal but tasy
- Fructose and glucose have the same chemical formula but different molecular structures
- They perform different roles in the body
- Glucose: body’s basic metabolic currency essential to the cycle that breaks down food, extracts energy from it and powers all cellular activities and is transported throughout the body in the blood stream
- Fructose metabolized by liver and more closely tied to fat conversion
Conclusion: There is a major gut-brain connection when it comes to why we consume a lot fructose and scientists need to find more effective ways to manipulate them via diet, drugs or other means