The idea of food addiction is a murky subject.

Many people discount the idea that you can physically be "addicted" to food. But regardless you know yourself when you have food or drink high in refined sugar that you get the energy crash soon after, and then you're left feeling hungry and craving more sugar. However, one American scientist has been researching the effects of high sugar foods on the brain, the metabolism and your hunger and cravings - and he found some alarming stuff. Dr Robert Ludvig, who is an expert in researching the effects of diet on hormones, metabolism, and body weight, was speaking on Dave Asprey's Bulletproof show. The Harvard School of Public Health Professor of Nutrition pointed to a study he did with two groups of people who were given milkshakes in a double blind test (so they couldn't identify which was which). The shakes were identical in the amount of calories and the proportions of proteins, fats and carbohydrates they contained. The only difference was that one contained fast-acting carbohydrate (the kind of sugars you'd see in a fizzy drink) and the other with slower digesting carbohydrate. Dr Ludvig explained that as expected the group drinking the fast-acting carb shake had higher blood sugar after consuming it, which then crashed several hours later. "At that point the participants reported feeling hungrier - then we did brain scans and the results were really remarkable," he told Bulletproof host Dave Asprey. "It turned out one area (of the brain) lit up like a laser. In every single subject it lit up after the fast-acting carb drink or 'high glycemic index' shake, but not after the low one." This area was the nucleus accumbens - which he explains is the dopamine reward/pleasure centre of the brain. "It's considered Ground Zero for the classic addictions - of cocaine, heroin and alcoholism," he continued. "It raises the possibility that these highly-processed, very rapidly digesting industrial foods we're eating today can hijack fundamental pleasure and reward systems of the brain. "It's one thing to feel hungry because your blood sugar is dropping, but it's a different thing if your nucleus accumbens kicks in because then your ability to resist that 500 calorie bear claw you see in the pastry shop is going to vanish." He added that hunger and cravings are a very difficult combination to fight. Dr Ludvig, who has written a book with his findings called Always Hungry?, said: "I think there's quite a strong line of investigation to suggest that certain foods profoundly undermine our metabolism in ways that are not all that different to many classic drugs of addiction." So the take-home message here is: try and limit your intake of high sugar foods and fast-acting carbs and switch to slow digesting carb sources like oats and sweet potatoes to stave off hunger, stop your cravings, and keep your blood sugar more stable. https://www.youtube.com/watch?v=8S2ENOvAOak