http://achieve-fitness.com/blog/2010/07/07/artificial-sweeteners-linked-to-obesity/
Reference: achieve Fitness

Ever since the birth of artificial sweeteners, we’ve wondered if there was a definite link between these popular sugar substitutes and weight gain, or more specifically, obesity. Varying opinions exist on this controversial topic and it’s difficult to filter through all the information and research out there, much of which has been discredited.
It’s rare that you see fit, lean people walking around drinking diet soda. And just the same, it’s rare to encounter someone who is struggling to lose weight who doesn’t have a 3 diet soda per day habit! Also, when you look at the major jump in the obesity epidemic, it coincides very definitely with the introduction of artificial sweeteners into large quantities of the American food supply. So, common sense tells me that there is a definite correlation between the two, but what does science and research say?
A huge body of research has proven that the human body undergoes a series of hormonal and physiological responses that prepare the body for food intake. This response can be initiated by something as simple as smelling or thinking about food. (We’ve all had the experience of having your mouth water when you smell your favorite treat baking in the oven).Your brain begins to send signals to your body to prepare for the arrival of nutrients in order to maximize nutrient absorption in the small intestines and to minimize the effects that the food will have on your natural hormone balance.
The trouble is, this same metabolic response occurs when the body is given the sweet taste that is contained within sugar substitutes. When you feed your body non-caloric and non-nutritive sweeteners like aspartame (Nutra Sweet and Equal), saccharin (Sweet and Low), or sucralose(Splenda),it gets confused. These sweeteners make the brain start to send the signals that calories are on the way and trigger a whole set of metabolic responses and hormone surges. However, when the calories don’t arrive, your brain tells your body to go out and get them! Your appetite naturally increases, even if you’re full, and cravings usually come in the form of high carbohydrate foods to quickly fill the void and feed the insulin response that has already occurred.
A great study was published in the Journal of Behavioral Neuroscience by a group of scientists, doctors, and medical researchers from Purdue University which closely examined the effects of artificial sweeteners on weight gain. The researchers gave two different groups of rats some yogurt, one batch sweetened with natural sugar and one with saccharin, then monitored their behavior, eating habits, and physiological changes over the next few weeks. Their findings were eye opening.
The researchers found that the total food consumed over the next 14 days dramatically increased only in the artificial sweetener group. Despite them taking in fewer calories from the yogurt itself, their overall caloric intake following the consumption of the artificially sweetened yogurt increased substantially. Second, this group gained a significant amount more weight than the natural sugar group, and of course, their body fat increased as well. The third finding was that the rats that were fed the artificial sweeteners actually lost several degrees in their core temperature, which is a definite sign that their metabolism slowed down.
So, not only did the artificial sweetener group of rats gain more weight and body fat, but their metabolism was indefinitely affected, which led to increased caloric intake well after their initial intake of the sugar substitute.
The point is, not all calories are created equal. Quality can be just as important as quantity. When foods are low in calories, they don’t necessarily translate into being good choices for weight loss. Furthermore, artificial sweeteners are just that – artificial. The human body is not designed to metabolize chemicals or other unnatural substances! Though sugar is obviously not the answer for weight loss either, at least your body recognizes it and can metabolize it naturally.
One final thought if you’re still not convinced. The number of Americans who consume products that contain sugar free sweeteners grew from 70 million to 160 million from 1987 to 2000. During this same time period, the incidence of obesity in American has doubled from 15 percent to 30 percent. In addition, within this time frame, the number of Americans who are considered overweight has grown from 30 percent to nearly 65 percent! Wow!
So what’s the bottom line? Avoid artificial sweeteners like the plague! Your weight loss efforts and your overall health will thank you!