Over the holidays I had the beautiful opportunity to reconnect with some family that I hadn’t seen in many years. One conversation with my aunt really got me thinking. She told me how she had converted to a vegan diet, to control her blood sugar. Her side of the family is disposed to developing Type 2 Diabetes, so she watches her blood sugar, trying to avoid getting it, herself. She was having a really difficult time controlling her blood levels, even eating healthfully, and she was at risk of “pre-diabetes.” Her doctor wanted to put her on Metformin, but she is hoping to avoid that by using diet instead. Veganism has worked really well for her.

I was very interested, because I would have assumed that the opposite diet—a keto-type diet— would have been more beneficial for controlling blood sugar. After all, protein does not spike glucose levels, right? Not knowing a huge amount about the subject, I would have guessed that vegan diets were higher in carbohydrates. I asked my aunt if she knew what the mechanism is behind the vegan diet and T2 diabetes, and she didn’t know. She had only heard from various people that it worked, so she was trying it. And sure enough, her blood glucose remains at much better levels when she sticks to vegan foods. On busy days when she eats an omnivore type diet, her blood glucose goes up. So the vegan diet is working for her! The proof is in the chia-cashew pudding, right?

This fascinated me, so I tried to find the science behind it. Unfortunately, to say the world of nutrition science is murky, would be a monumental understatement. There are thousands of “expert” opinions out there about what you should eat, and why, and they all supposedly have some kind of scientific research behind them. You can find science supporting veganism, and science opposing it. The same goes for keto, Mediterranean, paleo, and literally any other diet out there. (The same goes for most supplements and any other fad wellness trend as well, by the way.)

I could not find anything convincingly definitive, but there are a few hypotheses as to why veganism might help with insulin resistance and blood sugar:

1. FIBER. A vegan diet may be higher in fiber than other diets, because of the large quantities of vegetables and fruits eaten. Fiber lowers blood glucose by reducing the speed of the uptake of carbohydrates into the system.

2. AMINO ACIDS. Animal protein is built of different amino acids than vegetable protein, and may have detrimental effects on blood glucose, so removing animal protein from the diet avoids this effect. (See also this study on plant protein and non-essential amino acids.)

3. GUT BACTERIA. A combination of 1 and 2 above— Increased fiber + decreased animal protein may affect the gut microbiome by encouraging the production of certain bacteria that produce the chemicals that support glucose metabolism and reduce insulin resistance in the body.

Remember, these are hypotheses, not necessarily hard facts. As I said, nutrition science is really difficult to work through. In fact, I don’t believe that science will ever be able to give a definitive answer as to whether a vegan diet will (always) prevent T2 Diabetes, because of the extremely important fact that:

Every. Body. Is. Different!

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It is true that a vegan diet greatly helps some people avoid T2D and remain in good health, as I learned from my aunt’s personal experience. But I also know from several other friends’ personal experiences that some people do very poorly on a vegan diet. Even when they supplement properly and eat the proper range of foods, they become sick and weak. Biodiversity is the only explanation for this. There is no one-size-fits-all approach to diet, because each body responds differently to the same stimulus.

Although science can paint in broad strokes (e.g. cigarette smoke is usually pretty bad for everyone), it cannot tell us “the best diet,” because the search for “the best diet” is meaningless. There is only “the best diet for YOU,” based on your unique physiology and circumstances. Science, (in its current state, anyway) can just give us clues. Its reductionist approach is not built for the type of complexity involved in these kinds of questions.

However, healers have known for millennia that people needed to customize their diets individually. Consider this incredibly apt quote from Hippocrates, who lived around 400 BCE, in his text “On Ancient Medicine”

Pretty amazing, right?

Temperament

For centuries, doctors and herbalists followed the theory of temperament to give them a rough way to divide up different types of bodies, and narrow down the wide array of medical options and lifestyle advice available. Many herbalists today, myself included, still use temperament in their practices. Temperament theory (in Western cultures anyway) was originally based on the idea that there are 4 fundamental elements that comprise the entire universe.2 These elements correlate to “humors” in the body. Everyone has a mixture of all the humors, but the humor that is dominant in any one person will define their physical and mental characteristics. These are called the temperaments

I don’t think most herbalists today believe that bodies are literally composed of 4 elements that produce physiological differences between people. However, the four temperaments scheme is a helpful mnemonic and a useful place to start. There are different schemes for defining the temperaments, but the one I use is:

• Choleric — hot + dry — the Fire element

• Melancholic — dry + cold — the Earth element

• Phlegmatic — cold + wet — the Water Element

• Sanguine — wet + hot — the Air Element

Each temperament has a set of typical physical predispositions, baseline behaviors, and unique physical needs. For example, the hot temperaments (Choleric and Sanguine) tend to digest food quickly, while cold temperaments (Melancholic and Phlegmatic) have slower digestion. The ancients said that hot temperaments had “stronger digestive fire” than cold temperaments.

Many herbalists rely on physical and behavioral observations to “diagnose” someone’s temperament. You can take whole classes on it, and it’s quite fascinating. As an astrologer, though, I have a shortcut: the birth chart! There are astrological methods that have existed for hundreds of years, that help a medical astrologer define someone’s baseline temperament.

OK, so how could I apply this to my aunt’s situation?

My aunt is of a religious persuasion that is offended by astrology, unfortunately. I did not ask for her birth data to pull a chart, because…

Relying on observations, I would guess that my aunt is Melancholic in temperament. She is always wearing layers, indicating to me that she probably runs cold. She is fine-boned with taut, smooth skin. Personality-wise, she is soft-spoken, detail-oriented, practical, and introverted. These and other clue point strongly to the “Earth” or “Melancholic” element.

In the temperament scheme I use, the Melancholic temperament would be well suited to a diet that is high in vegetables. While the hotter temperaments may need more meat (which is considered a “hot” food), colder temperaments may do better with lots of vegetables (most of which are considered “cold”). It is interesting to note that many vegetables contain certain amino acids that are normally produced by the body (so-called “non-essential” amino acids.) So by eating vegetables with these AA’s, we are giving the body a shortcut. It doesn’t have to expend the energy normally required to build these amino acids on its own; it can just absorb them from the plant. If the body is not getting the signal, "I have to make proteins now," it might not send the signal to call for more blood glucose for extra energy. This correlates well with the idea of vegetables being “cold” foods: coldness is lower in energy than heat. Cold foods require less energy and do not tax the body the way hot foods do. Our ancestors knew nothing about amino acids when describing vegetables as “cold” all those years ago, but here we have some preliminary science supporting this idea.

Thus, one rule of thumb I use, when people ask me if they should do extreme diets like keto or veganism, is how much heat or cold they have in their temperament. Keto would work better with the hot temperaments, and veganism would work better with the cold temperaments.

NOTE: Ahhh!!! There are a LOT of other things to consider besides this! Things are not this binary! This is just a place to start. And in general, I am not a fan of extreme diets anyway. I tend to be a “moderation in all things” type of gal. But when you are wanting to correct a specific situation, like pre-diabetes for example, it might make sense to work with an extreme diet for awhile.

So with my aunt, it seems that she has found a diet that fits not only the health goal she is trying to achieve (avoidance of diabetes), but also that fits with her temperament. And that should be everyone’s goal. If we eat in ways that contradict our physiology, we will suffer, but if we eat in alignment with our temperament, we will feel really good.

They say “you are what you eat.” I would add another aphorism—

Eat for what you are!

If you are interested in exploring your temperament based on astrology, I offer beautiful, detailed temperament reports.

I also offer health coaching, if you would like to explore how diet, herbs, and astrology can help with a specific health or wellness concern you may have.