The research is starting to pile up linking AS consumption to lymphomas, leukemias, cancers of the bladder and brain, chronic fatigue syndrome, Parkinson's disease, Alzheimer's disease, multiple sclerosis, autism, and systemic lupus. After understanding the "excitotoxin" effect of AS in the body, especially in the brain, these diseases should not be a surprise. The real paradox is many people use AS to lose weight but studies actually show the opposite is true. There is no doubt that refined sugar is unhealthy but AS is not better. Since AS stimulate the brain, it promotes more eating later and less portion control. Remember, AS are ULTRA sweet, sometimes 100's of times sweeter than sugar so this can really stimulate the part of our brain that will cause us to crave more sweets later.2
A link that was always tough to nail down is to cancer. A recent study did show that leukemia risk increased in men who consumed more than 1 diet soda a day. The risk was greater than those that consumed sugar-containing soda. So again, AS comes out worse than even sugar.3
There are numerous websites and youtube videos dedicated to showcasing the negative effects of AS. Many are hardline, unscientific and dramatic but there are a handful that provide excellent information on the negative effects of AS like aspartame. I encourage you to explore them for yourself to learn about some of the foods that contain AS. Here is a link to a interesting interview with an integrative neurologist, Dr Russell Blaylock, who has dedicated much of his career to educate people on excitotoxins.
I have also attached a really nice review of the topic from a more scientific perspective if anyone is interested.
The bottom line for me is AVOID them. Even if they were safe (which they are not), they do not help you lose weight and may even cause you to over eat and gain more. They over-excite the brain and most likely cause cancer and neurological dysfunction. AVOID them and choose naturally occurring sugars from fruit, agave and raw honey.
1) Bandyopadhyay A, Ghoshal S, Mukherjee A Genotoxicity testing of low-calorie sweeteners: aspartame, acesulfame-K, and saccharin. Drug Chem Toxicol. 2008;31(4):447-57.
2) Fowler SP, Williams K, Resendez RG, Hunt KJ, Hazuda HP, Stern MP. Fueling the obesity epidemic? Artificially sweetened beverage use and long-term weight gain. Obesity (Silver Spring). 2008 Aug;16(8):1894-900.
3)Schernhammer ES, Bertrand KA, Birmann BM, Sampson L, Willett WC, Feskanich D. Consumption of artificial sweetener- and sugar-containing soda and risk of lymphoma and leukemia in men and women. Am J Clin Nutr. 2012 Dec;96(6):1419-28