In a new analysis of studies involving more than 406,000 patients, researchers found that people who substitute artificial sweeteners for sugar – even the natural kinds – actually gained weight, instead of losing it. 
Published in the Canadian Medical Association Journal, the study looked at the long-term effects of artificial sweeteners on heart health, weight, stroke incidence, and blood pressure levels.
The researchers wrote:
“We found that consumption of nonnutritive sweeteners was associated with modest long-term weight gain in observational studies.”
Artificial sweeteners were once touted by doctors as healthy for diabetics who didn’t want to give up sweets, but who also realized that continuing to eat sugar could cause serious complications or death. But the analysis showed that the consumption of artificial sweeteners may increase a person’s risk for developing the disease, and other potentially serious health conditions.
The team says:
“Our results also extend previous meta-analyses that showed higher risks of type 2 diabetes and hypertension with regular consumption.”
Some of the Findings
For the analysis, researchers reviewed 30 studies that followed groups of people that used artificial sweeteners, including aspartame (Equal), sucralose (Splenda), and stevioside (Stevia). The studies involved in the review including longer, larger studies with follow-ups every 4-9 years. Study participants not only gained weight using artificial sweeteners, they also had higher risks of obesity, high blood pressure, and stroke.
Specifically, the observational studies noted a small increase in body mass index (BMI) associated with consumption of artificial sweeteners, a 14% greater chance of developing Type 2 diabetes for those who consumed the most artificial sweeteners, and a 32% higher risk of cardiovascular events for those who ate the most, compared to those who ate the least. 
Those who had hoped to lose weight in the short-term were met with disappointment; participants in the 7 shorter randomized, controlled studies reviewed in the analysis didn’t show consistent weight-loss after 6 months.
Lead author Meghan Azad, of the University of Manitoba in Winnipeg, Canada, said:
“From all that research, there was no consistent evidence of a long-term benefit from the sweetener, but there was evidence for weight gain and increased risks of other cardiometabolic outcomes.” 
Tricked into Poor Health
The fact that sugar causes obesity and a host of other health problems is fairly common knowledge these days, but the reason why artificial sweeteners appear to do the same things is less understood. To put it in simple terms, artificial sweeteners “trick” the brain into thinking the body is consuming real sugar.
See, artificial sweeteners are chemically different than sugar. When you taste something containing artificial sweeteners, receptors are activated on the tongue that lets the brain know you are eating or drinking something sweet. 
When you eat something sweet, the brain’s reward center is activated by a surge of dopamine. Leptin, an appetite-regulating hormone, is also released. When you eat something with calories, leptin eventually signals to your brain that you are full.
However, when you eat something sweet but with no calories, your brain’s pleasure pathway still gets activated, but the lack of calories means there is nothing to shut it off.
In turn, your body signals that it needs more calories, which results in carb cravings. In the end, you wind up eating more than you should, taking in more calories than you should, and those carbohydrates get converted into sugar.
Artificial sweeteners have been shown to alter gut microbes, some of which have been linked to obesity.
Furthermore, researchers have discovered that artificial sweeteners alter metabolic pathways linked to metabolic disease.
Stevia is considered the “safest” artificial sweetener, because it is natural. However, if you have high blood pressure, high cholesterol, diabetes, or extra weight, then you have insulin sensitivity issues, and you should probably avoid artificial sweeteners entirely.
According to a study published earlier in 2017, 1/4 of U.S. children and 41% of American adults consume artificial sweeteners, most of them at least once per day. Though people likely consume more artificial sweeteners than they realize, since they’re in everything from granola bars to yogurt. 
Your safest bet is to learn to enjoy your coffee black, and choose foods free of sugar and artificial sweeteners.
Easier said than done, I know, but you can do it!
 ABC News