Tag: Knowledge recall

Growth hormone increases significantly during fasting—sometimes 2-5 times baseline levels within 24-48 hours. Research by Ho and Hartman found five-fold increases during 40-hour fasts. GH is powerfully muscle-preserving, signaling the body to maintain lean tissue while burning fat for fuel. This is why fasting doesn’t cause the muscle loss that simple calorie restriction might—the hormonal environment is different. This companion covers what growth hormone does, the fasting effect on GH secretion, why this matters for muscle preservation, and practical implications for intermittent fasting and exercise. (4 min read)

Calorie-dense foods pack many calories into small volumes; nutrient-dense foods deliver high nutrition relative to calories. Research by Barbara Rolls shows people eat a consistent weight of food—lower calorie density means more volume with fewer calories. Vegetables are 0.1-0.5 cal/gram; oils are 9. The ideal: high nutrient density, low calorie density. This companion covers both concepts, why calorie density matters, the optimal combination, and practical application for building meals. (3 min read)

Leptin is the satiety hormone—released by fat cells to tell the brain “we have enough energy stored.” Research by Friedman discovered leptin in 1994, but subsequent studies found that people with obesity often have high leptin levels—the problem is leptin resistance, where the brain doesn’t hear the signal. Despite abundance, the brain perceives starvation. The fix isn’t more leptin but restoring sensitivity. This companion covers leptin’s intended function, the resistance problem, what causes it, and how to address it. (4 min read)

The protein leverage hypothesis: humans have a strong drive to consume specific protein amounts. Research by Simpson and Raubenheimer shows if protein is diluted by carbs and fats, we overeat total calories to hit our protein target. A drop from 15% to 10% protein can increase intake by 12%. Modern processed foods are low-protein — the body keeps seeking. This companion covers the discovery, human evidence, why protein is defended, the processed food problem, and practical implications. (3 min read)

At 12 hours, you’re transitioning out of the fed state. At 18 hours, fat burning accelerates. At 24 hours, full fasted metabolism with significant ketone production. Research by Anton on flipping the metabolic switch shows each milestone represents deeper shifts into fasted metabolism. At 36 hours, autophagy ramps up aggressively. This companion covers what happens at each fasting window, individual variation factors, and practical applications for matching fasting durations to your goals. (3 min read)

Your body defends a particular weight with surprising persistence. Research by Leibel and Rosenbaum shows that when you lose weight, metabolic rate drops, hunger hormones increase, and energy expenditure decreases—all pushing you back toward previous weight. The “Biggest Loser” study found persistent metabolic suppression years later. You’re not fighting just habits; you’re fighting physiology. This companion covers evidence for set point, defense mechanisms, evolutionary reasons, whether it can change, and working with your biology. (5 min read)

When animals are given access to a variety of highly palatable foods rather than standard chow, they massively overeat and rapidly become obese. Research by Sclafani and Rolls documented how variety and palatability drive overconsumption independent of caloric need. The modern food environment is a giant cafeteria diet experiment—endless variety, engineered palatability, and predictable results. This companion explores the original cafeteria experiments, why variety drives overconsumption (sensory-specific satiety), why palatability overrides satiety, the modern cafeteria parallels, and practical implications for simplifying your food environment. (4 min read)

Ghrelin is the “hunger hormone” that rises before your usual meal times—not because you’re running low on energy, but because your body expects food. Research by Cummings showed ghrelin peaks preprandially, before meals, not in response to fuel depletion. Crucially, hunger comes in waves: ghrelin spikes, peaks, then recedes on its own within about two hours. If you wait out the wave, it passes. You can also retrain ghrelin by changing eating patterns. This companion covers ghrelin’s role, the learned schedule, hunger waves, the circadian connection, and practical implications. (4 min read)

Four qualities create lasting satisfaction without overconsumption: high protein, high fiber, high water content, and low caloric density. Research measuring 38 foods found boiled potatoes scored 323% on the satiety index while croissants scored just 47%. Fat, surprisingly, had a negative correlation with fullness per calorie. This companion explores the satiety index, the four factors that predict fullness, why this explains which eating patterns work, and how to choose foods that satisfy naturally. (4 min read)

Protein triggers insulin, but differently than carbohydrates—through direct amino acid stimulation, not blood sugar spikes. Research by Holt on the insulin index shows protein-rich foods stimulate significant insulin despite low carb content. Protein also triggers glucagon, which partially offsets insulin’s effects. Fat has minimal insulin impact. The result: protein causes a more moderate, balanced hormonal response supporting satiety and muscle preservation. This companion covers carbs and insulin, protein and insulin, fat and insulin, and practical implications for meal design. (3 min read)