One important caveat must be mentioned; all experiments involved food and water deprivation. Thus, the observed activation of the dopamine reward system by calorie load in this paper may be affected by the food-restricted state of the mice.
This study raises many intriguing future questions. How is calorie load sensed by the dopamine reward system? Do certain sugars (for instance, fructose) affect the dopamine reward system in different ways? Does the same phenomenon occur when calories come from different food types? For example, do calories from fat have a stronger affect? All of these questions are important to understand the underlying causes of human obesity. Understanding the rewarding properties of certain foods will help us to design effective ways to restrict the desire to eat once the need to eat is fulfilled. This study also adds to the growing body of information showing that metabolic cues are not solely the domain of the hypothalamus and that much more crosstalk occurs between metabolic cues and higher brain centers involved with the desire to eat than previously believed. Thus, categorizing food intake as hedonic versus homeostatic may not only be redundant but misleading. When it comes to eating, need and desire aren’t so separate after all.
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10 Comments
Add CommentCould it be that food corporations already knew this - and that is why SUGAR is packed into nearly every food in this country?
Reply | Report Abuse | Link to thisObesity will decline when we stop "processing" everything so much and when we stop adding sugar to everything.
Of course they know this. In the 19th century, the nutrition experts decided that Americans were too thin, and needed to put on weight. Their solution - add a little sugar to everything. The Fannie Farmer cookbooks exemplify this. American food is full of sugar, compared to the European countries that many of us count as our ancestors. Europeans don't add sugar to bread, yoghurt, beets, sausage, soup, etc. The low fat diets just make this worse, since taking the fat out removes the taste, so they add sugar to make the food palatable.
Reply | Report Abuse | Link to thisWhy are corporations and processing always vilified? They have both done so much for us that gets constantly ignored every time someone wants to duck personal responsibility.
Reply | Report Abuse | Link to thisEvery thing's always a conspiracy
There's no conspiracy. Sugar makes things taste good, and people prefer sweet foods. Thus, sweet foods sell better. It's a business move. The consequence of which is making people fat. However, if people could exercise a bit of personal responsibility and put down the Twinkies they might be able to keep the weight off. Fruit is pretty sweet, eat fruit instead of that chocolate ice cream.
Reply | Report Abuse | Link to thisPeople need to quit pointing the finger everywhere else and point it at themselves. That being said, I think this article does a good job illuminating the process. Perhaps if none of us could taste sugar, we would be better off. People eat too much and get fat because they enjoy eating. I think that's perfectly reasonable. Now, people just need to learn to override this "enjoyment" and actually work to maintain their health.
I suppose it's just too convenient to eat whatever we want and do nothing to maintain our health... since it takes little work to shovel food into our mouths and an extra hour or two of hard work every day to exercise, not to mention all the thought involved in eating foods that are good for us, checking calories, balancing the diet, etc...
Thanks for rational people! Those conspiracies will eventually get you candide! It could be the fluoridated water, or perhaps vaccines, maybe digital televisions... but with all those people plotting against you, and it is all of us plotting against you, I don't know how you can take it!
Reply | Report Abuse | Link to thisAny person in America that can read should know what calories are, how many they actually use a day, and how many they take in with every meal and what kinds of calories they take in. If you don't know, it's your own fault. You should know how much you burn through different activities. But I don't blame everyone for not knowing, most Americans live in caves with no contact no contact with the outside and without access to huge informational databases through the internet. right? Corporate America is probably hiding that information as we speak.
What you put in your mouth is your business, nobody is putting it there for you. If you must become obese through your own inability to regulate your diet, then the best we can hope for is that your body gives out before you reproduce. A far better solution than limiting what the rest of us can eat.
Thanks for reminding me I'm not alone!
Reply | Report Abuse | Link to thisI have to admit it's hard to accept personal responsibility in this case. there's millions of years of evolution that has chosen those that eat everything in sight. Hopefully science will provide us with the nutritional equivalent of birth control so we can live with our evolutionary traits.
I generally agree, except on one point. The article states that mice preferred the sucrose-laced water over the sucralose-water, indicating that the calories themselves are pleasurable for those mice (which can't taste sweetness.)
Reply | Report Abuse | Link to thisSo it is possible that even if we couldn't taste sweetness, we would still crave calories, and still become obese.
Most Americans don't care enough about losing weight or else they would be doing more about it. It's kind of the same principle as why most Americans have credit card debt. We need to burn more calories so we can lose more lbs and decrease health care costs. Alas, we'll see what happens in the future.
Reply | Report Abuse | Link to thisI think its time to replace the rewarding or reward prediction theory of dopamine with incentive salience theory of dopamine(berridge et al). These results are compatible with berridge's tema's data that showed a dissociation between liking and wanting food/sweetness. As dopamine just marks the incentive salience of a stimulus, t would be activated even if the food was unpalatable as long as it was salient (provided calories in food-deprivation) states. I dont know what additional information, than what has already been done in th incentive-salience framework, does this study shed light on.
Reply | Report Abuse | Link to thisI don't think they need to know it, Candide.. we all already know that sweet is delicious, so they were probably just responding to that.
Reply | Report Abuse | Link to thisCarlchwe: I don't know about that. If there was no reward, we probably wouldn't eat so much. But we'd still eat the same type of things we do now.