Our Body — An Understanding

Pancreas — beta cells

Sends the sugar in the blood into the cells. The rest it stores in the liver and in fat tissue. This is the "storage hormone" — as long as it stays high, the body will not burn fat.

Within minutes of eating. Starch and sugar raise it most; protein a little; fat very little.

Fibre-rich vegetables, whole grain, fenugreek, cinnamon, magnesium (greens, nuts, sesame), good fats, ghee with rice.

White sugar, refined flour, cold drinks, high-fructose corn syrup, fruit juice on its own, a late dinner, frequent snacking.

Pancreas — alpha cells

Insulin's opposite. It turns the glycogen stored in the liver back into sugar and releases it into the blood. This is the hormone that protects the brain while you fast.

On an empty stomach; while fasting; in the early morning; during long exercise.

A decent gap between meals, protein, walking, fasting.

A snack every two hours — without a gap, this is never released at all.

Adrenal cortex

The hormone that lifts the body in the morning. It raises blood sugar, damps down inflammation, and meets stress. A friend over a short span; an enemy over a long one.

At its peak around six in the morning; very low at night. At any hour at all under stress.

Vitamin C (gooseberry), magnesium, enough sleep, meditation, deep breathing, a walk in the sun.

Lack of sleep, too much caffeine, waking in the night, a long hard fast combined with stress.

Adrenal medulla

The "fight or flight" response. It raises heart rate, breathing rate and blood pressure all at once, and sends sugar to the muscles.

Fear, anger, sudden exertion, a cold-water bath, the early morning.

Deep breathing, savasana, walking — these settle whatever is in excess. A measured cold bath trains it.

A tense environment, too much caffeine, screens before bed, the news.

Pineal gland

Brings on sleep; renews the body; a powerful antioxidant. The messenger that tells every cell what time it is in nature.

It begins to be secreted between 9:30 and 10:30 at night and peaks between 1 and 3 in the early morning. Very low at midday. If light falls on the eye, the secretion stops.

Full darkness at night; morning sun (by way of serotonin); banana, nuts, milk; sleep before ten.

Screen light at night, lamps, a late meal, caffeine, night work.

The brain; but ninety per cent of it in the gut

Governs cheer, calm, memory, appetite, fear and drive. At night this same thing turns into melatonin. Which is to say, tonight's sleep is made this morning.

Rises in daylight; increases with exercise and with sugar. In darkness it falls away and turns into melatonin.

A twenty-minute walk in the morning sun; food carrying tryptophan (nuts, seeds, banana, sesame); gut health; fermented food.

Staying indoors all day, stillness, gut trouble, trying to raise it with sugar alone.

Brain

Drive, attention, the sense of reward, control of movement. The satisfaction of "I finished it" comes from this.

On reaching a goal; in novelty; in anticipation; after exercise.

Protein (tyrosine), exercise, sunlight, reaching small goals — the one-method-a-day shape of this book exists for exactly this.

Sugar, social media, gambling — these drive it to an artificial peak and blunt the capacity to feel ordinary small pleasures.

Pituitary and hypothalamus

The body's own painkiller. Reduces inflammation; brings contentment.

Exercise, laughter, music, meditation, spicy food. After nine at night its level falls away of its own accord.

Walking, yoga, sun salutation, laughter, music, worship in company.

Solitude, stillness, long-running stress.

Anterior pituitary

Cell growth, repair, muscle and bone, skin, renewal. Anyone who does not secrete enough of it ages faster.

In the deep sleep before midnight — particularly between 11 and 12 at night. It rises with fasting and with strength training.

Sleep before ten; fasting; an oil rub (abhyanga); strength training; enough protein.

Food before bed — sugar above all; waking in the night; going to sleep after midnight.

Thyroid gland

Sets the speed of the body's metabolism. Body heat, heartbeat, the pace of digestion, clarity of thought, hair and skin — all of it depends on this.

Secreted continuously; governed by TSH from the pituitary.

Iodine (sea salt, seaweed), selenium, zinc (pumpkin seed, sesame), iron, enough calories.

A very long, hard fast — it lowers T3 and makes the metabolism sluggish. Too much soy. Anyone taking thyroid medication should do the fast days in this book only after asking their doctor.

Parathyroid glands — four of them

Keeps the level of calcium in the blood exactly right. If the food does not supply it, it takes it from the bone.

The moment blood calcium falls.

Calcium (sesame, finger millet, greens, drumstick), vitamin D (sunlight), magnesium, vitamin K2.

Vitamin D deficiency, too much salt, the phosphoric acid in cold drinks, too much caffeine.

Begins in the skin, and finishes in the liver and the kidneys

It is not really a vitamin at all, but a hormone. It affects four things — calcium absorption, immunity, insulin sensitivity and mood.

When midday sun falls directly on the skin.

Twenty minutes of sun a day; mushrooms, eggs, fish. Dr Hyman links vitamin D deficiency directly to insulin resistance.

Being indoors the whole time; always covered up; a life the sun never touches.

Fat tissue

The hormone that tells the brain "enough, stop". It reports how much energy the body is holding in store.

When fat stores rise; within a few hours of eating.

Enough sleep, fibre, omega-3, food that reduces inflammation, a gap between meals.

Lack of sleep, too much fructose, processed food. These produce "leptin resistance" — and then, though the stomach is full, the message never reaches the brain. This is the biological reason behind the habit of overeating.

Stomach

The one hormone that says "I am hungry". It also triggers growth hormone.

When the stomach is empty; and also just before the usual mealtime, as though it had read the clock.

Regular meal times, enough protein, enough sleep.

Lack of sleep raises ghrelin — which is exactly why hunger is greater the day after a sleepless night.

One thing to know on a fast day: hunger is a wave. It comes, it peaks, and it subsides by itself. Get past that wave and the rest of the day is easy.

Small intestine

Prompts insulin to be released; slows the emptying of the stomach; gives the brain a sense of fullness. Many of today's weight-loss drugs are simply a synthetic form of it.

When food reaches the small intestine — particularly when there is fibre, protein and fat in it.

Fibre, protein, fermented food, a healthy gut flora, eating the vegetables first.

Sugar in liquid form, food stripped of its fibre, refined flour.

Adrenal cortex

Holds on to sodium and water, and so steadies blood pressure.

When the body runs short of water or salt; when blood pressure falls.

Steady, regular drinking of water; balanced salt; potassium (tender coconut, banana, greens).

Long thirst; a sudden flood of water; too much salt.

In dehydration the body looks for salt — and that, Moritz says, is the reason behind a craving for too much salt. If the craving for salt fades, it means the water balance has returned.

Posterior pituitary

Makes the kidney draw water back in, and so guards the body's water balance.

When the body runs short of water; it is secreted more at night — which is why you can sleep without needing to pass urine.

Drinking water a little at a time, all through the day.

Alcohol and caffeine suppress ADH and drive water out of the body. At night they bring dehydration and broken sleep together.

Made in the hypothalamus, released from the posterior pituitary

Bonding, trust, calm. It lowers cortisol; eases blood pressure; speeds the healing of wounds. It is central in childbirth and in breastfeeding.

Touch, an embrace, affectionate talk, eating together, time with a pet.

Eating with the family, an oil rub, worship in company, a walk with a friend.

Solitude, living only behind a screen.

What Dr Hyman says applies here — being connected to other people is one of the raw materials health is made from. That is not a poem; it is the name of a hormone.

Ovaries; a little in the adrenals and in fat tissue

The menstrual cycle, bone density, skin, mood, memory. Progesterone sustains pregnancy; it brings calm and sleep.

Across a cycle of about twenty-seven and a half days — estrogen in the first half, progesterone in the second.

Fibre (which carries surplus estrogen out), flaxseed, sesame, calcium, a steady weight, enough good fat.

Hot food in plastic, too much alcohol, a diet with far too little fat, long-running stress.

If the fast days in this book clash with your menstrual days, move the fast. A woman's body has a cycle of its own besides the moon's; that one takes precedence.

Testes; in women the ovaries and adrenals, in far smaller amounts

Muscle, bone density, energy, drive, libido, clarity of mind.

At its peak in the early morning — the sex hormones reach their highest level around six. They rise with strength training too.

Strength training, deep sleep, zinc (sesame, pumpkin seed), vitamin D, good fats.

Lack of sleep, too much alcohol, long-running stress, belly fat.

So that insulin does not rise at night; so that growth hormone is released in deep sleep.

Because the digestive enzymes and the bile are at their peak only then.

Melatonin begins to be secreted between 9:30 and 10:30; growth hormone between 11 and 12.

Serotonin; and through it the night's melatonin; vitamin D.

So that glucagon is released; so that insulin falls; so that fat burns.

So that leptin sensitivity returns; so that you learn the wave of ghrelin.

So that growth hormone and the cell's own cleaning reach their peak.

Growth hormone; oxytocin; less cortisol.

Oxytocin — food eaten alone will not give you that.

So that GLP-1 is released; so that the rise in insulin stays gentle.

So that leptin's "enough" message reaches the brain.

Insulin stores the sugar in the blood inside the cells; glucagon takes out what was stored in the liver. Insulin while you eat; glucagon while you fast. Giving each of them its turn is the biology of fasting.

Leptin says "enough"; ghrelin says "I am hungry". When sleep is short, ghrelin rises and leptin falls — which is why someone who has not slept eats more the next day.

Melatonin is the hormone of the night; cortisol the hormone of the morning. When one rises the other must fall. If screen light reaches you at night the two get confused together and the day's rhythm breaks.

One takes calcium from the bone and puts it into the blood; the other takes it from the blood and puts it back into the bone. Sunlight and vitamin D keep this see-saw level.

Adrenaline is the "fight or flight" state; acetylcholine is the "rest and digest" state. While eating it is the second state that is needed — which is why you should not eat carrying stress, or in a hurry.

As long as insulin stays high, growth hormone is secreted less. Fasting and deep sleep lower insulin and make room for the work of repair.

Dopamine says "I want more"; serotonin says "what I have is enough". Sugar and screens drive dopamine up and push serotonin down.

The pair that governs the two halves of the menstrual cycle. One builds, the other steadies. This is the reason women should ease the severity of fasting in the second half of the cycle.