Watermelon occupies a specific and carefully delineated role in the Primal Diet. It is categorized as a fruit, specifically a high-sugar fruit when the heart is consumed, but a low-sugar, therapeutically active food when the rind and the flesh immediately surrounding the seed belt are used. Aajonus described it as the single best food on the planet for causing perspiration, making it central to his protocols for lymphatic detoxification, hot bath support, and athletic hydration. It is also the most potent natural source of the compound citrulline, which he consistently described as a natural Viagra, affecting both male and female genital function. Because of the dramatic divergence in properties between the heart (high-sugar, problematic) and the rind and adjacent flesh (low-sugar, therapeutically active), Aajonus treated watermelon almost as two entirely different foods depending on which portion is consumed. The rind is also a significant source of collagen precursors. Watermelon appears as a core ingredient in multiple versions of the Sport Formula and Sport Drink, which are his primary hydration protocols.

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Watermelon causes more perspiration than any other food. Aajonus stated this consistently and emphatically across many workshop contexts:

This perspiration-inducing property was directly linked to lymphatic detoxification. Aajonus explained that if a person has problems with the lymphatic system, which he stated that "everybody does", watermelon should be consumed a minimum of three days per week to assist in clearing that system. The specific instruction was to eat the flesh from where the seeds end down to the rind, avoiding the high-sugar heart. The connection to perspiration was also given in combination with body heat: in the sport drink context, it was noted that watermelon equals perspiration and body heat.

He further stated that when watermelon is combined with avocado, the perspiratory effect is noticeable almost immediately after eating:

He applied this specifically to people who have never perspired in their lives, noting that watermelon combined with regular hot baths would help initiate the perspiratory process, particularly in people who had been long-term vegetarians and had built up residues of vegetable oils such as safflower and sunflower oil.

The compound citrulline is described as the key active ingredient in watermelon rind, and Aajonus returned to this property in nearly every detailed discussion of watermelon. Citrulline is concentrated most heavily in the white rind and in the small pink area adjacent to it. The red heart contains far less.

The physiological effect of citrulline as Aajonus described it:

He explicitly applied this to both males and females with equal emphasis. For males with erectile dysfunction, he gave a specific protocol: eat watermelon rind for three to four days, consuming approximately two cups of rind per day. By the fourth day, even a small amount was sufficient to maintain the effect. He stated this worked on approximately 90% of his clients with erectile dysfunction.

Aajonus described his personal experience with the rind's effect on erection:

He also noted that this effect, while physiologically beneficial, could be unwanted in some circumstances:

He also described an experiential note about the combined effect of the heart: eating the sweet center of watermelon creates both arousal and irritability simultaneously, which he described as a "terrible combination":

The rind of the watermelon is explicitly described as high in collagen precursors. Aajonus connected this directly to the citrulline effect, suggesting the collagen precursor concentration may be the reason the rind has such a pronounced effect on penile and clitoral tissue:

In the sport formula context, he described the collagen precursors in the puree (cucumber, tomato, watermelon) as the reason pureing is used rather than juicing, the pulp retains the collagen precursor content, which would be lost in juicing.

The watermelon also replaces collagen under the skin more broadly:

Watermelon was specifically noted as high in natural sodium:

This sodium content makes watermelon and avocado together a concentrated, natural sodium source. Eating the two together was described as producing a heavy concentration of good natural sodium, after which most people will begin perspiring almost immediately if the weather is warm.

In the early training materials, Aajonus described watermelon as being extremely rich in Vitamin A:

High-Vitamin-A fruits were described as calming for people with nervous disorders.

In one passage, Aajonus introduced a caution about citrulline and heart disease, though this appears in a context where he is speaking about the rind broadly:

This statement is not fully elaborated in the surrounding text, and appears to stand in tension with his otherwise consistent promotion of the rind as beneficial. It is presented here without resolution as it appears in the source.

The flesh of watermelon from the seed zone inward to the rind contains high pectin:

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Aajonus divided the watermelon into four distinct zones, each with different properties and recommendations:

1. The heart (sweet center), The innermost red flesh. High in sugar, causes irritability combined with arousal, can create glycogen stickiness in the brain and nervous system, should be discarded or avoided.

2. The seed belt, The ring of flesh immediately surrounding the seeds. Bacteria in this zone are described as good for decomposition and breaking down tissue, but Aajonus specifically stated he did not eat tissue from this belt: "I don't eat any of the tissue in that whole belt where the seeds are."

3. The pink flesh from the seeds to the rind, This is the primary edible zone. Low in sugar, high in pectin, high in citrulline and collagen precursors.

4. The white rind, The highest concentration of citrulline and collagen precursors. This is the most therapeutically active zone.

5. The green outer skin, This is always discarded. Aajonus never ate or recommended the hard green outer skin.

He described his personal eating practice in consistent detail across multiple passages:

In one instance where he was eating in the tropics and wished to avoid mosquito attraction, he noted that he consumed only a tiny heart and all the white rind, avoiding the seed belt entirely.

Aajonus preferred watermelon unripe:

He described eating watermelon that was so unripe its flesh was pink rather than red, which indicated minimal sugar content. This is the form he preferred for regular therapeutic use, while acknowledging that even at this ripeness the rind remains active.

When asked about pickled watermelon rind, Aajonus explicitly stated that pickling degrades the citrulline effect:

The statement trails off in the source but the clear implication is that pickling significantly diminishes the therapeutic activity of the rind, particularly its sexual stimulant properties.

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The green outer skin must always be removed before consumption or use in formulas. This is non-negotiable in Aajonus's instructions:

The reason given in the sport formula context is that the green peel will turn the intestinal tract alkaline, disrupting the acidic bacterial environment needed for proper digestion of dairy, eggs, and meats:

Seeds must always be removed. The reason given is phytic acid:

The seeds were described as causing ill reactions from phytic acid. In the sport formula context, deseeding is listed as a mandatory preparation step.

Watermelon is always pureed, never juiced, when used in formulas. The distinction is critical because juicing destroys the pulp, which contains collagen precursors:

The technique is to slice or dice the watermelon after removing the green and the seeds, then blend it directly. This produces a thick puree that retains the fibrous pulp and all the collagen precursors within it.

He noted that because the puree ingredients are thick, the sport formula becomes something that must be chewed as well as sipped:

Aajonus acknowledged that watermelon is seasonal and tropical in origin:

In contexts where watermelon was unavailable, he provided substitution guidance: replace the watermelon cup with additional cucumber and tomato puree, and add a half cup of water to compensate for the missing volume. When watermelon is completely unavailable, the combination of tomato and cucumber carries forward the collagen precursor benefit, though without the citrulline and perspiration-inducing properties.

In one passage he described his experience in Bangkok, where he would fall back on lime juice, cream or butter, honey, and ginger when he could not obtain fresh juice, but would eat watermelon rind when he could get it:

Aajonus noted a personal observation that eating the high-sugar heart of watermelon correlated with mosquito bites:

However, when he restricted his eating to only the white rind (avoiding the seed belt and the heart), even eating watermelon every day in the tropics for two months resulted in no mosquito bites. He attributed this to the avoidance of the high-sugar portion and the particular bacteria in the seed belt zone.

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For any situation where the sweeter portions of watermelon might be consumed (or for people with blood sugar sensitivity), Aajonus consistently prescribed fat pairing:

Even with fat buffering, he maintained that the heart was not advisable. For the low-sugar rind and pink flesh, fat pairing was recommended but not with the same urgency.

For people with diabetes or blood sugar problems, explicit fat pairing instructions were given when any watermelon fruit is consumed:

Watermelon and avocado together create a high natural-sodium combination that maximizes perspiration:

In the Sport Formula, watermelon is always combined with eggs, dairy cream, coconut cream, vinegar, lime juice, lemon juice, and honey. This complex of fats, proteins, and acids ensures that the sugars in the watermelon are properly buffered and all nutrients are absorbable. The eggs and cream slow absorption and protect the nervous system from any glycemic spike that might come from the pink flesh.

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When eating watermelon for general purposes, Aajonus described eating a section per day as rare but acceptable:

His regular practice when in tropical environments was daily consumption of rind and pink flesh. In non-tropical contexts, he described it as an occasional food.

• Two cups of rind per day
• Duration: three to four days
• Maintenance after that: small amounts only

• Minimum three days per week when watermelon is available
• Portions unspecified but implied to be moderate (rind and pink flesh only, not heart)

• Total formula: approximately 1 quart
• Watermelon contribution: typically 1–2 cups of the 3-cup total base
• Warning: two cups of watermelon (rind and pink) in the sport drink alone will likely create excessive sexual arousal

• Small portions throughout the day rather than a large serving at once
• "Let's say this size, break it up into about four pieces", referring to a portion that fits in a palm
• Always paired with fat

The more unripe, the better for sugar-sensitive individuals. When so unripe that the flesh is pink rather than red, the sugar content is at its minimum.

Even if fat is consumed alongside the heart, some neurological stickiness remains. The heart is simply not recommended regardless of fat pairing.

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The simplest and most preferred method. After peeling the green outer skin, the white to pink flesh is eaten directly, raw, without preparation:

Aajonus noted that the rind tastes almost exactly like cucumber:

The standard preparation for sport formula use: 1. Peel the green outer skin off the watermelon completely 2. Remove all seeds (phytic acid concern) 3. Slice or dice the flesh 4. Place in a quart jar 5. Add all other ingredients 6. Blend together (blend for approximately 45 seconds, starting on low) 7. The result is thick, it is chewed as well as sipped

A simple pairing for sodium and perspiration support. No special preparation indicated, eat the two foods together in whatever amounts are appropriate.

Eating watermelon so unripe it is pink instead of red, consuming the pink and white portions with the green peeled off and seeds removed.

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Aajonus discussed at length the institutional interest in watermelon's citrulline content:

He described the process by which they would need to extract the citrulline:

This was framed as a corrupted derivative, taking a naturally occurring, food-bioavailable compound and processing it through toxic solvents to concentrate it into a pharmaceutical form. The implication was that the natural form (eating the rind whole) is superior precisely because the citrulline is accessible without toxic extraction solvents, and because the surrounding collagen precursors and other nutrients are present to support its activity.

There was also the reference to genetically modified watermelon:

This was framed negatively, the natural, unmodified watermelon rind already provides sufficient citrulline when eaten in its whole food state.

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Texas A&M University's efforts to genetically engineer watermelons with higher citrulline concentrations were mentioned multiple times as an example of institutional medicine attempting to capture natural food properties and convert them into patentable pharmaceutical products. The problem, as Aajonus explained it, is that the extraction process requires toxic industrial solvents (kerosene or hexane), turning what is naturally available and biocompatible in the whole rind into something that carries solvent contamination.

Aajonus's personal multi-year observation that eating the high-sugar heart of watermelon reliably led to being bitten by mosquitoes, while eating only the rind prevented mosquito bites even over two months of daily consumption in tropical environments, suggests a biochemical change in body chemistry or skin secretions driven by the sugar content of the heart versus the low-sugar rind.

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