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At first, the mice on the fatty diet ate the same amount of food by weight as the others, but still got more calories because fat is energy-dense.
Descriptive
Even normal mice have a more complicated daily rhythm of stress hormone than just one peak—it has two peaks, and this is true for all mice, not just those on a fatty diet.
Even if they eat the same amount of food by weight, mice on a fatty diet take in way more calories because fat has more energy than other nutrients.
Quantitative
The daily pattern of stress hormone in the mice’s poop is more complicated than just one peak—it has two peaks, and this complexity changes with diet.
Even though the mice on the fatty diet got heavier, the increase in stress hormone in their fur wasn’t linked to how fat they became—it seems the diet itself caused the change.
Correlational
Mice on a fatty diet not only weigh more, but also have a lot more body fat and a higher BMI, meaning they’re much fatter than mice on a normal diet.
The time of day when the stress hormone peaks shifts from daytime to nighttime in mice eating a high-fat diet, which is the opposite of what normally happens.
The natural daily rise and fall of the stress hormone in the mice’s poop becomes flatter and stays higher all day when they eat a fatty diet.
Mice eating a fatty diet have more of the stress hormone in their fur, suggesting their bodies are under more prolonged stress over time.
Mice that eat a high-fat diet start snacking more during the day—when they normally sleep—and eat less at night—when they normally are active.
When female mice eat a diet full of fat for a month, they get much heavier than mice eating a normal diet, and this starts happening after just two weeks.
After eating carbs, scientists measured changes in blood flow and nerve signals in the lower leg using special tools, and saw all the changes happen within two hours.
Eating carbs makes your body naturally release insulin for a short time—this is different from when doctors give insulin through an IV for a long time.
When insulin goes up after eating carbs, it lines up with bigger blood flow to muscles, looser blood vessels, and more nerve signals telling vessels to tighten—suggesting insulin might be linked to all these changes happening together.
After eating carbs, the body turns up the 'stress signal' to blood vessels, but the vessels still open up instead of tightening—meaning the body’s normal 'squeeze' signal isn’t strong enough to block the opening.
When healthy people eat a carb-rich meal, their muscles get more blood flow and their blood vessels relax, even though their body also sends signals to tighten blood vessels—this might help their body absorb sugar from the meal better.
Eating a meal with less protein makes you eat more calories — but not because you’re hungrier. Something else about the meal is making you eat more.
Eating a meal you choose yourself makes you eat more that day and a little less the next day — but then you go back to normal.
What you eat in one meal matters more for how many calories you eat that day than how hungry or full you feel.
When people on a high-protein diet eat a meal they choose themselves, their total calories go up — but they don’t feel any different in hunger or fullness.
Eating less protein makes people eat more calories — but not because they feel hungrier. Something else is going on.
How full or hungry people feel doesn’t explain why they eat more or less after choosing their own meal.
People on a high-protein diet usually pick one meal a week to eat whatever they want — and when they do, they eat more that day but don’t feel any hungrier or fuller than usual.
People can eat a lot more without feeling hungrier — meaning something other than hunger might be making them eat more.