Why Calories Don't Count — Interactive Mindmaps

Key concepts: Chapter 1: Calories, Calories Everywhere

Chapter 1: Calories, Calories Everywhere

The Core Question

• What makes a calorie count remains unresolved
• Endless food options and advice create confusion
• Uncertainty about real numbers shapes every meal

Baseball vs. Football

• Football's violence makes its 16 games decisive
• Baseball's 180-game season drains individual importance
• Long baseball games turn spectating into eating occasions
• Ballpark food becomes the natural centerpiece of fan experience

The Author's San Francisco Lens

• San Francisco spans just seven miles each way
• Author grew up in the city, attending St Ignatius and UC Berkeley
• Oracle Park and the Giants anchor the narrative
• Personal history frames the baseball/food dynamic

Key concepts: Introduction

Introduction

The Calorie Paradox

• Calorie counts promise to rank foods from good to bad
• A 1,400-calorie hot dog vs 900-calorie burger raises questions
• Do lower numbers mean better, and are all calories equal?

Defining the Calorie

• Small-c calorie heats 1 ml of water by 1°C
• Food labels use kilocalories (kcal), 1,000 times larger
• One calorie equals 4.184 joules
• Book uses 'calorie' to mean kilocalorie

Nutrition Labels and Serving Sizes

• Labelling compulsory in many regions, but not all foods
• UK/EU list energy, fat, carbs, protein, salt; US adds trans fats
• Serving sizes often smaller than typical portions
• Menu labelling voluntary in UK; US requires chains with 20+ locations

Lavoisier and the Birth of Calorimetry

• Conservation of mass: matter neither created nor destroyed
• Respiration is slow combustion, proven with guinea pig calorimeter
• First calorimeter measured heat via melted ice
• Bomb calorimeter developed in 1878 for food energy

Three Different Calorie Numbers

• A: energy actually in the food
• B: number printed on the pack
• C: energy the body can extract
• Only C matters for weight; getting from A to B requires Atwater

Key concepts: Chapter 2: The Atwater Factor

Chapter 2: The Atwater Factor

The Calorie Myth

• Labels measure machine burning, not body digestion
• Food structure and processing change calorie availability
• Sugar yields 95% energy, sweetcorn far less

Atwater's Method

• Three stages: collate, burn, feed and subtract
• Five components: water, ash, protein, fat, carbs
• Named extracted value 'metabolisable energy'

The Atwater General Factors

• Fat set at 9, carbs and protein at 4, alcohol 7
• Beat Rubner's rival figures by including faecal losses
• System stuck for over a century

Protein and Nitrogen Arithmetic

• Protein inferred from nitrogen using 6.25 factor
• Actual nitrogen ranges 13-19%, factors 5.26-7.69
• Jones factors replaced universal 6.25 in 1931

Carbohydrate by Difference Flaw

• Remainder lumps sugars, starch and fibre together
• 1970: simple sugar factor set at 3.75
• 1998: dietary fibre factor set at 2 calories

Human Body as Machine

• Atwater-Rosa calorimeter tested four men 1898-1900
• First law of thermodynamics held in humans
• Alcohol fuelled work identically, angering Methodist backers

Lulu Hunt Peters and Diet Culture

• Lost 70 pounds by strict calorie counting
• 1918 book sold two million copies
• Turned calorie counting into patriotic rationing

Key concepts: Chapter 3: How Do We Turn Food into Energy?

Chapter 3: How Do We Turn Food into Energy?

The Energy Puzzle

• Food energy obeys first law of thermodynamics
• Body converts energy safely at body temperature
• Two steps: digestion and intermediary metabolism

Digestion: From Mouth to Bloodstream

• Chewing and salivary amylase start starch breakdown
• Stomach acid and pepsin fragment proteins
• Small intestine absorbs nutrients via villi
• Fat travels as chylomicrons, not dissolved in blood

ATP: The Energy Currency

• ATP is a rechargeable molecular battery
• Energy released by splitting third phosphate
• People cycle 50-75 kg ATP daily

The Mitochondrial Pathway

• All nutrients funnel into acetyl-CoA
• Krebs cycle loads electrons onto NADH and FADH2
• Electron transport chain builds proton gradient
• ATP synthase turbine produces three ATP per turn

Carbohydrate Metabolism

• Glycolysis yields net two ATP anaerobically
• Without oxygen, pyruvate becomes lactate
• Full glucose oxidation yields thirty ATP
• Oxygen powers sustained energy past one minute

Gluconeogenesis and the Cori Cycle

• Liver rebuilds glucose from pyruvate
• Liver maintains blood glucose between 4-7 mM
• Muscle lactate returns to liver as glucose
• Acetyl-CoA cannot be converted back to glucose

Fat, Protein, and Starvation

• Fat oxidation yields 106 ATP per palmitic acid
• Glycogen stores last a day; fat lasts months
• Surplus amino acids become fat
• Starvation produces ketones to fuel brain