Tag: Knowledge recall

Glucose can be used by every cell in your body. Fructose is handled mainly by the liver, which takes 50 to 70% of it on the first pass. Intake has climbed from about 15 grams a day to about 55 over the past century, and at that load the liver’s capacity can be overwhelmed and fructose converted to fat, one route to fatty liver, in a process that parallels alcoholic liver damage, but from sugar. On this page’s view, the liver pays the price for America’s sugar consumption. This companion covers the metabolic difference, what happens in the liver, and…

With food and activity held constant, sleep deprivation shifts two key hormones: ghrelin (hunger) up 28% and leptin (satiety) down 18%. The cortisol story usually told alongside them is one this evidence does not carry in either direction. Research by Spiegel and Van Cauter found two nights of restricted sleep in twelve healthy young men produce measurable effects, with intake held constant. Left to eat freely, people on short sleep overeat anyway, while those same hormones read energy surplus. Both results are real, and together they say something better than either alone: bad sleep makes people eat more, and hunger…

The same reward circuitry that responds to addictive substances responds to hyperpalatable food, and brain imaging finds the parallel with large effect sizes: heightened reward-circuit activation to food cues alongside reduced activation of inhibitory regions while eating. But the strongest evidence for tolerance, withdrawal, and escalation comes from rat studies whose own authors concluded only that this may translate to some human conditions, and the food-addiction model remains scientifically debated: human imaging results largely conflict, no addictive agent in food has been identified, and binge-eating treatments do not match the model’s predictions. None of that makes the experience less real.…

The thermic effect of food is the energy spent digesting and processing what you eat. Protein is highest at 20-30% of the calories consumed: eat 100 calories of protein and 20 to 30 go to processing it. Carbohydrates are 5-10%, fat 0-3%. Two things are easy to blur, though: the overall figure is a share of daily energy expenditure rather than of a given meal, and it is a range that moves with what you eat, roughly 5 to 15%. The bar for “enough” protein also sits lower than the usual advice: 1.2 to 1.6 g per kilogram of body…

Homeostasis is the body’s drive to maintain stable conditions, including body weight. Research reviewed by Rosenbaum and Leibel shows that when you diet, the body responds to the deficit with countermeasures: hunger increases, metabolism decreases, food becomes more rewarding. These aren’t willpower failures: they’re biological responses to the deficit itself. The body doesn’t know you’re trying to lose weight, and it defends against losing far harder than against gaining. This companion covers what homeostasis does, the diet response, and working with biology rather than against it. (5 min read)

Body fat is survival insurance, on the usual evolutionary reading. Leibel and Rosenbaum found the body responds to weight loss by increasing hunger and dropping metabolism beyond what the smaller body explains. Why it does is a separate question with a separate answer: the dual intervention point model reasons that the lower boundary reflects starvation risk under strong selection. Your body responds to weight loss as if starvation has begun. This defense mechanism doesn’t know about grocery stores or desk jobs. Understanding this isn’t fatalism; it’s knowing what you’re working with. This companion covers evolutionary logic, what fat does, and…

Processing often transforms food in ways that reduce nutrition and work against satiety. Research by Hall at NIH found participants spontaneously ate 500 more calories per day on ultra-processed foods versus whole foods matched for nutrients, and the same twenty people gained about two pounds on that diet and lost about two pounds on the unprocessed one. Gain and loss in the same bodies is what makes it causal rather than anecdotal. Fiber is stripped, structure destroyed, water removed, then sugar-salt-fat added. This companion covers what processing does, the controlled study, and why processed food may drive overconsumption. (5 min…

Calorie density is calories per gram of food. A 2009 paper by Rolls illustrates the size: for someone eating about 1,200 grams of food a day, reducing density by a tenth of a calorie per gram at the same weight works out to roughly 120 fewer calories. Low-density foods (vegetables, fruits) carry more volume per calorie, while high-density foods (oils, chips) pack hundreds of calories into small volumes. Stomach stretch responds to volume rather than to calories, though it is one input among several rather than the switch that ends a meal. This companion covers the numbers, why density matters,…

Hyperpalatable foods combine fat, sugar, and salt in proportions that no fresh fruit, meat, or fish met in one study. On a common account, satiety evolved around whole foods, and it often falls short against these combinations. “Can’t eat just one” isn’t a character flaw: it’s a predictable response. This companion covers what makes food hyperpalatable and the satiety override. (4 min read)

Highly rewarding foods activate the brain’s reward circuitry in patterns resembling those seen with addictive drugs, a blood-oxygen signal rather than dopamine. Gearhardt’s fMRI work, in 39 young women with the key contrast resting on fifteen against eleven, is where that comparison comes from. Fazzino quantified hyperpalatable combinations: fat + sugar, fat + salt, carbs + salt. Fazzino’s team says such combinations may facilitate overconsumption despite satiety. This companion covers the reward system basics, what makes food highly rewarding, why reward drives overconsumption, brain imaging evidence, and practical implications. (4 min read)