Hunter-gatherers typically ate in a compressed window, going 12-16 hours between dinner and breakfast, with little to no snacking in between. But the modern eating cycle has expanded dramatically - the average person now consumes food for 15 hours of their waking day, with a 75% increase in snacking just since 1978.

This constant consumption runs counter to the body's evolved circadian rhythms. During a fasting period of 12-16 hours, the body shifts into a regenerative state called autophagy, breaking down old cellular debris and essentially "taking out the trash" to optimize function. But we short-circuit this process by keeping insulin elevated with frequent meals and snacks.

Most eating is now prompted by environmental cues like time of day or availability of treats, rather than actual physical need. Nutrient researcher Satchin Panda recommends limiting eating to a 10-12 hour window to restore healthy metabolic cycles, with benefits for glucose control, inflammation, cognition and cellular cleanup.

Section: 1, Chapter: 15

Author: Michael Easter

For many, compulsive overeating serves a crucial emotional purpose. It soothes anxiety, numbs trauma, fills voids of loneliness and boredom. It's a way to "feed" unmet needs. So when a drug like Ozempic suddenly removes the overeating outlet, it can trigger a kind of psychological earthquake. Difficult emotions come flooding back. Stressful situations feel overwhelming without food to soften the edges.

For some, it may even trigger a switch to other compulsions like alcoholism. Before starting weight loss drugs, it's crucial to understand "what job overeating was doing for you" and to line up alternative coping tools. Ozempic may block destructive eating behaviors, but it doesn't automatically resolve their emotional drivers.

Section: 1, Chapter: 8

Author: Johann Hari

Even if you manage to lose weight, you likely did it in the same environment (family, job, commute, city) that made you obese. This environment will constantly tug you back:

• Junk food is still ubiquitous, cheap, heavily marketed - you swim in it
• You likely still face the stress, emotions, lifestyle that led you to overeat
• Your family/social habits around food may not have changed
• You now face intense biological backlash from your own body

Some determined individuals can white-knuckle their way through this, but it's not a realistic solution for populations. To reduce obesity, we can't just say "have more willpower" - we have to actually change the environment we all live in.

Section: 1, Chapter: 6

Author: Johann Hari

Protein is the one macronutrient you don't want to restrict. Guidelines:

• Aim for at least 1.6g/kg daily; up to 2.2g/kg if active
• Prioritize high-quality complete proteins
• Distribute into 3-4 feedings of 0.4-0.55g/kg each for maximal muscle protein synthesis
• Vegans/vegetarians need ~20% more to account for reduced bioavailability and completeness

Section: 3, Chapter: 13

Author: Peter Attia

After a week of stalking caribou with minimal food, the author experiences persistent, gnawing hunger - an unfamiliar sensation for someone used to constant access to calories. But the hunger also brings mental clarity and a kind of energized focus.

Neuroscience shows that hunger is a key driver of motivation, prompting humans to explore, learn, and take risks in pursuit of a goal. When we have effortless access to plentiful food, we dull that inner spark. Intermittent fasting, whether for 12-16 hours overnight or for whole days, has been shown to:

• Improve insulin sensitivity and promote fat burning
• Increase BDNF, a protein that enhances memory and learning
• Trigger autophagy, a cellular cleanup process that optimizes performance
• Boost mental clarity and ability to focus

Section: 1, Chapter: 14

Author: Michael Easter

Food doesn't just satisfy physical hunger - it also provides entertainment, pleasure, and emotional comfort. Ultraprocessed foods are expertly engineered to fulfill all those needs too well.

Compared to whole foods, highly processed products are hyperpalatable, calorie dense, quickly digested, and portable and long-lasting. To defend yourself:

• Aim for single-ingredient foods 80% of the time. Don't keep tempting ultraprocessed snacks in the house.
• Stick to a structured meal schedule. Don't graze all day - give yourself a chance to feel true hunger.
• Pile your plate with fiber-rich foods first - salad, fruit, whole grains. They keep you full on fewer calories.
• Beware of "health halos." Organic/vegan/keto junk food is still junk food!

Section: 1, Chapter: 8

Author: Michael Easter