Browse evidence-based analysis of health-related claims and assertions
Pregnant women who drink a lot of diet soda with saccharin or sucralose are more likely to get gestational diabetes than those who don’t, with saccharin showing the strongest link.
Correlational
If a pregnant woman drinks a lot of diet sodas or eats lots of foods with artificial sweeteners, she might be more likely to get gestational diabetes, even after accounting for things like her weight and diet.
Several official health groups have looked at lots of science studies over and over, and they all agree that artificial sweeteners won’t hurt you if you eat or drink them in normal amounts.
Descriptive
When your body breaks down aspartame (an artificial sweetener), it turns into three things you already get from foods like meat, beans, and fruit—and your body doesn’t store them up over time.
Mechanistic
If you swap sugary foods and drinks for ones with artificial sweeteners, your body might burn more calories than you take in, causing you to lose fat and feel healthier in ways that matter for your heart and metabolism.
Causal
When people eat or drink things with low-calorie sweeteners like they normally do, studies show it doesn’t hurt their health.
Scientists test artificial sweeteners on animals using way more than humans would ever eat, then say it’s safe for people by dividing that huge dose by 100—but that doesn’t match how much people actually consume.
Even if you have existing health issues like diabetes, studies show that drinking diet soda or eating foods with artificial sweeteners doesn’t seem to make your health worse.
Just watching what people eat and seeing how healthy they are doesn't prove that the food is causing the health results — you need to test it by changing what people eat on purpose.
People who already have health issues like obesity or diabetes often switch to artificial sweeteners to help manage their condition—so when studies see that sweetener users have worse health, it might not be because the sweeteners caused the problem, but because people with the problem chose the sweeteners.
People who drink diet sodas or use artificial sweeteners often have health problems, but it might not be because the sweeteners cause the problems — maybe people who are already unhealthy are just more likely to use them.
Sugar alcohols give you some calories when you eat them, like regular sugar, but fake sweeteners like stevia or aspartame give you almost no calories at all.
A type of immune cell that calms down inflammation (Tregs) doesn’t help kill the Pneumocystis fungus, but it does stop the lungs from getting too damaged — like a brake on the immune system’s overreaction.
Surprisingly, blocking a signaling molecule called IL-9 helps mice clear the Pneumocystis fungus better — it seems IL-9 normally puts the brakes on a helpful immune response.
Even though a powerful immune signal called IFN-γ is made during Pneumocystis infection, the body can still get rid of the fungus without it — but without IFN-γ, the lungs get much more inflamed and damaged.
A specific type of immune cell (Th17) and its chemical signal (IL-17) are essential for the body to clear the Pneumocystis fungus from the lungs — without them, the infection gets much worse.
When people with weak immune systems have very low levels of a specific type of white blood cell (CD4+ T cells), they’re much more likely to get a serious lung infection called Pneumocystis pneumonia — these cells are crucial for keeping the fungus in check.
If obese adults with type 2 diabetes do supervised aerobic exercise like walking or cycling for 12 weeks, they’ll likely lose body fat and gain muscle.
When obese adults with type 2 diabetes exercise regularly, their muscle cells’ energy factories become longer and less round, which is a good thing—even if the usual control switches in the cell don’t change.
If obese adults with type 2 diabetes do 12 weeks of guided cardio workouts like walking or cycling, their bodies get better at using insulin to manage blood sugar.
After doing supervised aerobic exercise like walking or cycling for 12 weeks, obese adults with type 2 diabetes get better at using oxygen to make energy in their muscles—especially through one key energy pathway—and might also improve a couple of other related energy systems.
When obese adults with type 2 diabetes exercise hard for 12 weeks, five days a week, their muscle cells start to fix broken mitochondria—making them longer and less round, which might help the cells work better.
When rats with high blood pressure did 10 weeks of running on a wheel, they got much better at exercising—80% better—and even after just four days of stopping, they still kept most of that improvement.
Quantitative
Even though all the rats got heavier, those that ran on a wheel lost fat around their insides—suggesting exercise might target belly fat specifically, even when the body gains weight overall.