Did you know that MRI scans of the brain show that merely thinking about our favourite foods can activate the same brain regions (the hippocampus, insula, and caudate) involved in drug cravings? This fascinating insight, highlighted by Weingarten and Elston (1990), defines food cravings as an “intense desire to eat a specific food.”
What Makes a Craving?
For a desire to qualify as a craving, it must be powerful enough to motivate us to seek out a specific food. This differentiates cravings from general hunger, where a variety of foods would satisfy the need. It's crucial to recognise that food cravings can significantly impact dietary compliance, snacking habits, and even binge eating behaviours (Waters et al., 2001).
Interestingly, individuals following a repetitive, monotonous diet are more likely to experience frequent and intense food cravings compared to those consuming a more diverse, yet calorie-matched, diet.
Hunger vs. Appetite: Know the Difference
Despite the emphasis on calorie management in nutrition coaching, the fundamental understanding of hunger isn't as widespread as it should be. Over a century ago, Cannon and Washburn (1912) defined hunger pangs as “a physical feeling experienced in the upper abdomen.” This sensation is triggered by gut hormones like somatostatin and motilin, which cause contractions in the stomach and small intestine as the body clears undigested food and microbes.
Hunger is also closely linked to blood glucose levels, with low glucose indicating a calorie deficit. However, it's important to distinguish between hunger and appetite. Hunger is a physical sensation, while appetite is a psychological response to the sensory stimulation of food—whether it’s the sight, smell, taste, or texture.
How Long Does Satiety Last?
The sensation of hunger typically returns as the stomach empties. Remarkably, some people begin to feel hungry even when 40% of their previous meal is still being digested. A study by Sepple and Read (1989) found that all participants experienced hunger by the time only 20% of their meal remained in the stomach.
After consuming a large meal, the stomach stretches, and circulating levels of the hunger hormone ghrelin decrease significantly. This reduction in ghrelin signals that it’s time to stop eating. As the stomach returns to its normal size, ghrelin levels rise, and hunger returns.
The Satiety Index: Surprising Findings
A study published in the European Journal of Clinical Nutrition (Holt et al., 1995) introduced the concept of a “satiety index.” Participants were given 240 calories of various test foods and asked to rate how full they felt afterward. Surprisingly, when calorie-matched, potatoes scored 1.8 times higher in satiety than typical protein foods like steak. The worst performer? Croissants, which scored only 22% of the satiety rating of potatoes.
To put it into perspective, 240 calories equates to about 61g of croissant or 365g of potatoes. It’s clear that the greater volume of potatoes would take longer to digest, keeping you fuller for a longer time.
Key Takeaways
Understanding the difference between hunger, appetite, and cravings can help you make more informed choices about your diet. By focusing on foods that provide greater satiety, like those higher on the satiety index, you can better manage your hunger and reduce the likelihood of overeating.
Want more insights and tips on managing cravings and improving your diet?
Connect with me on Facebook or email me at paul@thenutritionistuk.com for personalised guidance from a Qualified Registered Nutritionist.
