Fit for Life

Diamond's most famous prescription is "fruit til noon." He builds it on three daily cycles he says govern the body: appropriation (eating, roughly noon to 8 p.m.), assimilation (absorbing nutrients, 8 p.m. to 4 a.m.), and elimination (removing waste, 4 a.m. to noon). Morning is the body's garbage-removal shift.

Eating a heavy cooked breakfast, he argues, hijacks that shift because digestion is the body's single largest energy expense. Fruit is the exception: since it requires almost no digestion, you can eat it all morning without interrupting elimination. He challenges readers to a one-week test: nothing but fresh fruit and juice before noon, then a normal diet, then a heavy breakfast on day eight to feel the difference in energy.

Fruit is the only food that needs no stomach digestion, Diamond claims, because its sugar is fructose, a monosaccharide the body can use almost directly. Eaten alone, it passes quickly to the intestines. Eaten on top of other food, it gets trapped, ferments, and turns acidic, causing the gas, bloating, and heartburn people wrongly blame on the fruit itself.

Two guidelines govern fruit:
1. Always eat it raw and unprocessed. Pasteurized juice is heated so intensely it becomes dead and acid-forming.
2. Always eat it on an empty stomach, alone.

He tells of a woman convinced she was allergic to strawberries since childhood, when the real culprit was the hot dog she ate them with. Eaten alone, the strawberries caused no reaction.

Diamond's third key is food combining. He asks readers to build lunch and dinner around one concentrated food, either a protein (meat, fish, eggs, dairy) or a starch (bread, pasta, rice, potatoes), plus cooked vegetables and a big raw salad, never protein and starch together.

His stated reason is energy conservation. Proteins need acidic digestive juices, starches need alkaline ones, and combining them supposedly neutralizes both, prolonging digestion and wasting energy the body could use for cleansing and weight loss. He credits this practice with ending the crippling stomach pain that plagued him from age three to twenty-five. His ex-wife's invention, the "Main Course Salad," makes this practical by tossing one concentrated food with vegetables into a single satisfying bowl.

Diamond's pacing philosophy is "speed is nothing, direction is everything." He rejects the rapid-loss fantasy, citing that dramatic crash weight loss returns, plus more, in about 95 percent of cases. He compares it to making three million dollars in a month and going broke by month six versus building income that lasts.

His target ratio is 50 percent living, 50 percent cooked food, but he insists there is no rush and no need to measure precisely. Someone starting at the American norm of 10 percent living food can simply double it to 20 percent and already trigger improvement. Lose a modest five pounds a month and you are thirty pounds lighter in half a year, permanently, with an eating pattern you can sustain rather than endure.

Diamond spotlights the lymphatic system as the body's "garbage collector." It gathers toxins from all cells, breaks them down, and routes them to the bowels, bladder, lungs, and skin. He notes the body holds roughly three times more lymph fluid than blood, underscoring its scale.

Crucially, lymph has no pump. Unlike blood, which the heart drives, lymph moves only through physical activity. This makes exercise non-negotiable for anyone trying to shed weight. He recommends modest, consistent movement, a brisk twenty to thirty minute daily walk, and endorses a mini-trampoline (rebounder) whose bouncing opens and closes lymph valves. He credits lymphatic cleansing with helping him survive Agent Orange exposure from Vietnam.

Diamond names dairy the single worst food in the human diet and argues the calcium-for-bones message is a marketing masterstroke. Humans are the only species that drinks milk after weaning, and the only one drinking another species' milk. Cow's milk is engineered to grow a 90-pound calf into a 1,000-pound animal in two years.

His central paradox: the countries consuming the most dairy (United States, Britain, Sweden, Finland) have the highest osteoporosis rates, while Asian and African populations who consume little have the least. He argues high-protein, acid-forming diets leach calcium from bones to neutralize acid, and that pasteurization plus milk's coarse casein protein make its calcium poorly absorbable anyway. Plants, he says, supply ionized calcium the body can actually use.

Diamond dismantles the protein anxiety that stops people from eating more plants. His argument is evolutionary and observational: the planet's strongest animals, elephants, oxen, water buffalo, gorillas, build massive muscle on leaves and grass alone. A cow makes its celebrated protein from grass.

The mechanism is amino acids. All protein is assembled from amino acids, which plants manufacture from soil, air, and water. When you eat chicken, you must dismantle chicken protein into amino acids and rebuild them into human protein anyway. Cooking meat, he adds, damages and coagulates those amino acids. He cites the China Health Project (Cornell, Oxford, and the Chinese government), which found Chinese people get about 7 percent of protein from animals versus 70 percent for Americans, with far lower rates of the "diseases of affluence."

Diamond's longevity argument rests on "metabolic enzymes." He divides enzymes into three types: food enzymes (in raw food), digestive enzymes (the body makes these when food enzymes are cooked away), and metabolic enzymes (which run every bodily function). He claims the body can produce only a finite lifetime supply, and that cooked food forces it to divert that supply into digestion, hastening death.

His evidence is gerontologist Roy Walford, who doubled the lifespan of mice by fasting them two days a week, resting their digestive tracts. Diamond's takeaway: streamline digestion to conserve life energy. He also promotes supplemental "Live Plant Enzymes" taken before cooked meals to spare the body's own reserves.