# Fruit

Category: Foods & Substances

Also known as: ripe fruit, tropical fruit

Fruit is the basic energy-efficient food, evolved specifically to support animal life and disseminate seeds, making it fundamentally compatible with human physiology. Peat argued that plants concentrate serious toxins in their bark, leaves, and roots, but create substances in…

10 passages · 2 authors · 1996–2023 · Most-cited: [Ray Peat](https://bioenergeticoracle.com/md/voices/ray-peat/index.md)

Canonical page: https://bioenergeticoracle.com/concepts/fruit

## Synthesis

**Fruit** is the basic energy-efficient food, evolved specifically to support animal life and disseminate seeds, making it fundamentally compatible with human physiology. [Source 3, 6] Peat argued that plants concentrate serious toxins in their bark, leaves, and roots, but create substances in the fruit that promote animal life, ensuring the animal lives long enough to spread the seeds. [Source 3] This evolutionary design positions ripe fruit, particularly from the tropics, as an ideal calorie source that provides a clean flow of energy from the sun to the brain, minimizing the side effects and disease associated with other foods. [Source 1, 3]

The *fructose* component of fruit is central to its metabolic advantages. Unlike pure glucose from starches, fructose does not require insulin for its metabolism and helps the liver produce more **cholesterol**, which, when thyroid function is adequate, serves as a precursor for protective hormones like **pregnenolone** and **progesterone**. [Source 5, 10] Peat noted that the combination of sugars in fruit results in a much lower glycemic index and glycemic load compared to starchy foods, which are 100% glucose and trigger a high insulin spike. [Source 10] Furthermore, fruit comes with many minerals that work in place of insulin and have a slightly suppressive effect on it, aiding in blood sugar stabilization. [Source 5] Dinkov has added that even among fruits, one should be mindful of preformed *serotonin* and *tryptophan*; he notes that very ripe pineapple and bananas are high in serotonin, and tryptophan is the only amino acid that is directly carcinogenic. [Source 4]

Tropical fruits are singled out as the ideal calorie source because they are likely to be reasonably low in iron, high in vitamins and minerals, and contain only small amounts of thyroid-inhibiting substances. [Source 1] Peat emphasized that fruits are a major source of **magnesium** without overloading the body on iron, and that seeds, in contrast, contain the worst plant poisons, which are metabolic and enzyme inhibitors. [Source 1] Well-strained, sweet orange juice is considered the safest fruit option, as indigestible fibers, including the chemically altered pulp in commercial juices, should be avoided. [Source 8] Other beneficial tropical fruits include papayas, the custard apple family, and mangoes, though poorly ripened fruits of all sorts, as well as common allergens like bananas and jack-fruit, should be avoided. [Source 1, 2]

A pure all-fruit diet over the long run presents a specific challenge because most fruits are very low in **iron**, though Peat suggested that a fairly low iron intake is tolerable if other metabolic factors are optimal. [Source 7] He also cautioned that in the U.S., a fruit diet might default to large quantities of bananas and dates, which are high in serotonin and can create inflammatory problems. [Source 7] The fruit's fiber and sugars stimulate the intestine, accelerating movement and keeping bacteria harmless, and Peat considered the flavonoids in fruit to be very beneficial, though not technically essential. [Source 7, 9] When fruit is unavailable, he recommended simply adding a little sugar to milk with coffee as a practical substitute. [Source 9]

## People also ask

### Why does Ray Peat consider fruit an evolutionarily ideal food for humans?

Peat argued that fruit evolved specifically to support animal life for seed dispersal, making it fundamentally compatible with human physiology, unlike other plant parts that concentrate defensive toxins.

### How does the fructose in fruit affect blood sugar differently than starch?

The entry notes that fruit's combination of sugars, including fructose, results in a lower glycemic index than starchy foods, and its minerals help stabilize blood sugar by slightly suppressing insulin.

### What is the main nutritional risk of a long-term all-fruit diet?

Peat cautioned that most fruits are very low in iron, and in the U.S., a fruit diet might default to bananas and dates, which are high in serotonin and can create inflammatory problems.

## Related concepts

- [Fructose](https://bioenergeticoracle.com/md/concepts/fructose/index.md)
- [Hyperthyroidism](https://bioenergeticoracle.com/md/concepts/hyperthyroidism/index.md)
- [Saccharide](https://bioenergeticoracle.com/md/concepts/saccharide/index.md)
- [Age Pigment (Lipofuscin)](https://bioenergeticoracle.com/md/concepts/age-pigment-lipofuscin/index.md)
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## Cited passages

Passage numbers match the `[Source N]` markers in the synthesis above.

### Source 1 — The Thyroid 1996 Gary Null Radio Show

Ray Peat · Interview · 1996 · http://l-i-g-h-t.com/files/gary-null-thyroid.mp4

> **Gary Null:** Remember, don't get too technical. We only have 2 minutes to go, and you gotta summarize.
>
> **Ray Peat:** Okay. The ideal calorie source, I think, is tropical fruits, and tropical oils, especially coconut oil, and any tropical fruit that lives at a high temperature -- papayas, the custard apple family, pineapples, anything that is full of carbohydrates, is likely to be reasonably low in iron and high in all of the other vitamins and reasonable for minerals. And they are important as a source of magnesium. Meat and shellfish and fish and so on give you quite a bit of magnesium, but the fruits are a major source of magnesium without overloading us on iron and the toxic substances. Because fruits in general, from the tropics, have small amounts of the thyroid inhibiting substances. Seeds in general have the thyroid inhibiting substances for a variety of reasons, namely the worst of them is that plants evolve poisons to prevent their seeds being eaten, because they wouldn't have a next generation if animals found the seeds palatable and safe to eat -- so the worst poisons plants have are put in the seeds, and they turn out to be metabolic inhibitors -- enzyme inhibitors. But the fruit, generally, is evolved to serve to distribute the seeds, so it's evolved to be safe to the animals. Potatoes are the only vegetable protein which is of quality equal to egg yolk. It's actually a little higher in quality because it contains precursors to the essential amino acids; it has more protein in effect than it actually has in substance. And people misjudge potatoes because they are given as 2 to 4%, because wet potatoes are measured, where beans are measured in the dry state and have 40% protein, but...you have to divide the bean protein by 10 to make it equivalent to potatoes.

### Source 2 — Email Exchanges — Fruit

Ray Peat · Email · 2015

> # Fruit
>
> Bananas and jack-fruit are strong allergens, possibly because of their cultivation methods. Mangos, apples, and pears are allergenic to some people. Poorly ripened fruits of all sorts should be avoided.

### Source 3 — Dr. Ray Peat, Day Two: Full Interview from On the Back of a Tiger

Ray Peat · Interview · Feb 18, 2021 · https://www.youtube.com/watch?v=Z3yVUELD2ZA

> **Perceive Think Act Films:** How did you come to believe or why do you think that fruit seems to be such an ideal or healthful food?
>
> **Ray Peat:** I think I was thinking about an article of J.D. Bernals in 1960. He was talking about the evolution of heavy atoms in stars and the sun. And that started me thinking about the nature of energy and matter in general. And just in the most generalized way that I could conceive in 1960, I was thinking of what the ideal flow from the sun to our brain would be what things would simplify and generalize that flow to reduce the costs in side effects, problems, disease, and so on. and looking at the flow of energy. Trees that could stay in place for many years, dropping their leaves to fertilize the ground. Humans putting their sewage back into the soil and eating the fruit as their main energy. The plants evolved Most of the things we consider edible fruits were specifically evolved to tempt and support animal life to disseminate their seeds. And so the plants would put really serious toxins in their bark. and leaves and roots, but they would create things that would promote animal life in the fruit so that the animals would live long enough to spread their seeds. So the environment is deliberately supporting animal life in the form of fruit. And ruminants have developed a system for detoxifying the environment that other animals have neglected. So if you put polyunsaturated fatty acid into a typical person or non-ruminant, About 98% of it survives into the system if it's quickly absorbed. 2% of it the bacteria can saturate. But the ruminants simply extended parts of their intestine to allow that kind of bacteria that can hydrogenate polyunsaturated fats to develop and cook their food before it gets into their system. So they have about 98% of their fats become saturated, where 98% of ours are remaining unsaturated. So the way a tree can continue producing fruit constantly, a cow can constantly continue converting vegetation into almost a perfect food.

### Source 4 — Low Carb, Cortisol and Glucose - Discussion Between Georgi Dinkov & Dr. Mercola

Georgi Dinkov · Interview · Jun 18, 2023

> **Dr. Joseph Mercola:** That's a game changer. So I interrupted you with the citric question, but you were in the process of explaining other fruits. And I'm wondering if you could touch on some fruits other than the... The citrate fruits and the sour fruits, which we should avoid, other than any others.
>
> **Georgi Dinkov:** Papaya, mango. I think even pineapple would be okay, but the pineapple has a relatively high amount of serotonin in it, preformed. So it really depends on how your digestive system functions. If you're getting loose stools from eating pineapple, chances are your serotonin is either already higher than... optimal, or the pineapple that you ate. And the more ripe the pineapple, the more serotonin it has, then it's probably you've eaten too much. So pineapple is not something to be eaten in liberal amounts. I think just a few chunks is enough. And the biggest benefit that I see from pineapple is improving the digestion of protein. If you look at these supplements that digest exactly the papain, they contain papain because it's closer in structure to our protease enzymes that are produced by the pancreas. So yeah, but again, ripe tropical fruits. So plums are probably okay.

### Source 5 — Your Own Health And Fitness: Nutrition And The Endocrine System

Ray Peat · Interview · Feb 11, 1997 · http://l-i-g-h-t.com/files/your-own-health-and-fitness-nutrition-and-the-endocrine-system.mp4

> **Ray Peat:** The fruit comes with many of the minerals which work in place of insulin and have a slightly suppressive effect on the insulin and the fruit has a strange side effect that it happens to promote cholesterol production and that's one of the reasons I emphasize having plenty of fruit sugar because the fructose while it doesn't cause obesity, it does help your liver to produce more cholesterol which is then available if your thyroid is functioning to turn into the protective hormones, pregnenolone and progesterone.

### Source 6 — Dr. Ray Peat, Day Two: Full Interview from On the Back of a Tiger

Ray Peat · Interview · Feb 18, 2021 · https://www.youtube.com/watch?v=Z3yVUELD2ZA

> **Ray Peat:** So it turns out that the two most compatible foods with our system and with the cosmic energy scheme Fruit is the basic energy efficient one. Milk is the practical conserver of energy and provider of a concentrated nutrient.

### Source 7 — One Radio Network: Vitamin D, Thyroid, Evolving Consciously

Ray Peat · Interview · Aug 20, 2019

> ## Fruit Diet
>
> **Patrick Timpone:** Have you heard of Morris Krok and the all-fruit diet?
>
> **Ray Peat:** Lots of fruits stimulate the intestine and accelerate movement, keeping bacteria happy and harmless. One problem with a pure fruit diet over the long run is that most fruits are very low in iron. You can tolerate a fairly low iron intake if everything else is good. In the US, you might end up eating a lot of bananas and dates, and those happen to be high in serotonin and can create problems of inflammation.
>
> **Patrick Timpone:** How would you get more iron on a fruit diet?
>
> **Ray Peat:** In studies of Pacific Islanders who live on a potato diet, once a year they have a pork feast—one week a year—and that's enough iron apparently.
>
> **Patrick Timpone:** Dr. Peat, thanks for being here.
>
> **Ray Peat:** Okay, thanks.

### Source 8 — Interview with Raymond Peat, Ph.D.

Ray Peat · Interview · 2011 · http://l-i-g-h-t.com/files/east-west-the-thyroid.mp4

> **Ray Peat:** Yeah, raw carrot, not a cooked carrot, because the carotene is an anti-thyroid factor, but you can even rinse off some of the carotene after you have grated or shredded it. But a lot of hypothyroid people control their symptoms for years just by having a daily raw carrot, because of the cleansing effect on the intestine and liver.
>
> **Josh Rubin:** What other foods are going to enhance that T4 to T3 conversion? We're hoping to do a whole show on sugar, because it's a huge topic. But, you talk about glucose, you talk about selenium…what are some other foods people should be eating to actually help to bring the thyroid to an efficient level, but also help with that conversion, the T4 to T3 conversion?
>
> **Ray Peat:** The very sweet, low fiber foods: filtered, well-strained orange juice from sweet oranges is the safest that I know of. And there are several tropical fruits, (probably a hundred tropical fruits) that are very safe and helpful. And one very odd food: if you have a centrifugal juicer, you can juice a raw potato and then cook the juice like you would scramble an egg, and you get rid of the starch, and you have a very safe, high quality protein and mineral formulation. In practice, good orange juice and a few other tropical fruits are very good for your liver and thyroid balance.

### Source 9 — Ray Peat Email Advice Depository — Post 629

Ray Peat · Email · Feb 17, 2021

> **Ray Peat:** [Mar 9, 2020] Do you drink orange juice or have other fruit? [No]
>
> **Question:** What are essential or useful nutrients other than sugar, minerals and vitamin C , good fruits can provide?
>
> **Ray Peat:** [Mar 27, 2020] I think the flavonoids are very beneficial, though not technically essential. They provide some essential amino acids too.
>
> **Question:** The fruits are good (better than bread, for example) for stabilizing blood sugar because of minerals and sugar, and good balance of these two?
>
> **Ray Peat:** [Mar 29, 2020] If the fruits are well chosen, for ripeness, digestibility, etc.
>
> **Question:** Several replies above, you recommended me to have some fruits in diet. I understand that most of the nutrients they provide are beneficial anyway, but since I can't have them at this point, is there something in particular that can make the biggest difference that I can try to find in another source?
>
> **Ray Peat:** [Mar 30, 2020] I just add a little sugar to milk, with a little coffee, when I can’t get fruit.
>
> **Question:** Do you think rosehip broth would be good for vitamin C? Is it safe to have every day?

### Source 10 — Why Some Sugar is Actually Good For You, & Methylene Blue too w/ Georgi Dinkov

Georgi Dinkov · Interview · Mar 21, 2019 · https://www.youtube.com/watch?v=R3pZoJZFKPQ

> **Georgi Dinkov:** grape juice, all of these juices, and they're, you know, I know the argument is always, well, you know, sugar would be restricting sugar because it raises insulin. Actually, the glycemic index and the glycemic load of most of the drinks that are with sucrose or even the fruit is very low because half of it is fructose, and fructose doesn't trigger, it doesn't require insulin in order to be metabolized. So if you want to follow your doctor's orders when they tell you to limit sugar, you can actually achieve most of it by drinking sugar but avoiding the starchy foods which are 100% glucose. And glucose is the one that really triggers this very high spike of insulin and then the insulin crash later. So the doctors that are recommending these things, many of them don't even know that regular sucrose and most of the fruit sugars that are available in ripe fruit, they actually have a much lower glycemic index and glycemic load compared to the starches.

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