Browse evidence-based analysis of health-related claims and assertions
When obese people eat more fat (as a percentage of their calories), their blood pressure and blood triglycerides go down—even if they don’t lose weight—making their heart health better.
Causal
After eating a high-fat, low-carb diet for three days, the pancreas releases less insulin right after you drink sugar — even though blood sugar goes up.
Descriptive
After eating a high-fat, low-carb diet for three days, the body releases more of a gut hormone called GLP-1 when you drink sugar water — even though blood sugar goes higher.
Eating very low-carb, high-fat food for just three days makes blood sugar spike higher after drinking a sugary drink, compared to eating a normal diet.
It’s hard to know exactly how much lowering cholesterol helps because factors like age, how long you take the medicine, and how heart problems are defined can change the results.
The reason drug trials and genetic studies show different heart benefits from lowering cholesterol might be because one looks at short-term drug use and the other looks at lifelong low cholesterol.
People born with genes that naturally keep their bad cholesterol low have about half the risk of heart disease over their whole life, compared to others.
Correlational
Taking statins to lower bad cholesterol by a certain amount can cut heart attack and stroke risk by about a quarter in the first year.
Kids who eat more calcium-rich foods tend to have less body inflammation, but this doesn’t seem to help their insulin resistance, meaning calcium’s benefit might be only for inflammation, not sugar control.
People with higher levels of 'bad' cholesterol in their blood are more likely to have heart attacks or other heart problems.
When kids go through puberty, their bodies become more resistant to insulin—even if they’re not gaining more weight or eating worse—which makes them more prone to diabetes during these years.
Kids with fat around their middle are more likely to have inflammation and insulin resistance—even if they eat well or poorly—showing that where you store fat matters more than just how much you weigh.
Obese kids with lower levels of a hormone called adiponectin tend to have worse insulin resistance, even if they have the same amount of body fat as other kids.
Obese kids who eat a lot of sugary foods and white bread tend to have worse insulin resistance—even if they’re not more overweight than other obese kids.
Kids who don’t eat enough magnesium-rich foods tend to have more body inflammation, even if they’re not more overweight than other kids.
Kids ate less artificial trans fat over 10 years, and their cholesterol got better — but the study couldn't say for sure if that was because of less trans fat or other changes in their diet.
Kids who eat the most saturated fat are more likely to have cholesterol levels that doctors worry about — even at age 6.
When kids eat less butter and more olive oil or fish, their bad cholesterol goes down — especially if they were eating a lot of saturated fat to begin with.
Over 10 years, Icelandic kids ate less butter and fatty meat, and their 'bad' cholesterol went down a little — showing that changing what kids eat can help their heart health.
When kids eat more saturated fat (like butter and fatty meats), their 'bad' cholesterol goes up a little bit — even at age 6.
Almost everyone who switched to a low-fat, high-carb diet saw their blood fat levels go up—only one person didn’t, which means this effect happens in nearly all people.
After eating, people on a low-fat, high-carb diet have higher levels of fat, sugar, and insulin in their blood for longer than when they eat a diet with more fat, which might stress the body over time.
When people eat less fat and more carbs, their blood fat levels (triglycerides) go up a lot—even if their cholesterol stays the same—and high blood fat is linked to heart disease.
When you eat the same number of calories from sugar or from bread or rice, you don’t gain more weight from the sugar — so sugar isn’t uniquely fattening.