High-protein diet: an experiment I won’t repeat
There are three macronutrients: carbohydrates, proteins and fats.
One of them is your secret key to unlock unbeatable time-in-range, insulin sensitivity and immense energy. The other two are keys that open the less likeable doors of insulin resistance, cardiovascular diseases, and of rollercoaster blood glucose.
Can you guess which is which?
If you’ve been following this blog for a while, you know that my experience points at carbohydrates asthe first secret key. Luckily enough, my anecdotal evidence is backed by science! Carbohydrates are the organism’s preferred source of energy, and as long as they are whole and plant based, they will guarantee your best A1c.
Logically, the remaining two keys that open to the “danger” zones are proteins and fats. These are essential macronutrients of course, but not in the proportions that most people consider normal, and definitely not from the sources that people typically get them from (processed foods, oils and animals).
Testing them all: high-carb, high-fats and now high-proteins!
After comfortably achieving 90% time in range on a consistent basis by eating high-carb, I have decided to test what high-fats and high-proteins regimens would affect me. I have recently posted about the terribly high levels of blood glucose and insulin intake (and overall disruption of my health in any other respects) caused by an increase in fats and processed foods consumption. During those 10 days I felt the worst I’ve felt in years: I slept worse, I recovered worse, I could not focus, I felt low in energy and frustrated because I was unable to control my daily health. A dangerous experiment I won’t repeat for sure, but I now have my own empirical evidence and know why I will never eat that stuff again.
The only missing piece of the puzzle was protein. Proteins are praised by many, especially in the fitness community as the key macronutrient to build muscle and to be healthy. To no surprise a large number of people prioritise them over other nutrients, especially carbohydrates. The common sayings that “carbs make you gain weight” while “proteins build muscles” may sound rather convincing and easily persuade one to give proteins a larger share of the dish.
But are these claims true at all? What is the real price of a protein centric diet for a diabetic?
That sounded like a fairly curious question to answer, so The Curious Diabetic went on a quest to figure that out!
The high-protein experiment
Before jumping in, here are some notes to consider about my experiment:
I didn’t change the quality nor the quantity of carbohydrates. For me, this amounts to around 400g coming from plant based and whole carbohydrate rich foods, such as fruits and intact whole grains.
My fats intake was the ideal range, accounting for about 10% of my daily energy intake - in my case, around 30-40g per day.
The recommended amount of protein is (bodyweight (kg)) X (a factor ranging from 0.8 to 1.6), depending on the activity level. I run four times a week and lift weights three times a week, so I am rather active. My weight is approximately 65kg, so my ideal protein intake should be between 100-120 grams per day.
During the experiment, I went way beyond that ideal threshold, averaging 170 grams of daily proteins, all coming from whole plant based foods like chickpeas, lentils and beans and only a minimal amount from slightly processed sources like sugar free soy milk. The goal was to intentionally eat very large amounts of what are considered excellent (or “green light”) sources of protein, create an excess, and see how my blood glucose and my insulin intake evolved as a consequence of that.
Proteins and insulin resistance
Proteins, just like fats, are a leading cause of insulin resistance. In fact, they make you insulin resistant not only individually, but they can also compound each other’s effect! For a deep dive, I recommend reading this article that well describes how fats and proteins contribute to insulin resistance:
“Lipid- and protein-induced insulin resistance is particularly problematic in patients living with type 1 diabetes because the inclusion of both fat and protein worsens postprandial glycemic control within hours of a single meal and can significantly complicate blood glucose control.”
So, despite coming from clean sources like legumes, the excess I was creating still produced the expected damage: high fasting blood glucose, higher insulin needs and in turn a lower insulin/carb ratio - which signals a decreasing insulin sensitivity.
Other than confirming the detrimental impact of excess dietary proteins on blood glucose and insulin sensitivity, the fact that this occurred while avoiding processed foods somehow reinforced the common saying “the dose makes the poison”: you don’t need to indulge on junk proteins, even too many lentils can give you trouble!
How too many proteins impacted my blood sugar levels
Similarly to what happened during my experiment with fats and junk foods, my blood glucose during the day was going up and down within acceptable values (80-170). Definitely not stable, but also not alarming at first. Real problems started to show as soon as I hit the bed: every single night I went to bed with a perfect BG (around 120) and woke up to something close to 260.
You can see the image below that summarises the Dexcom data during the experiment.
That is exactly what happens when one gets most of their energy from nutrients that promote insulin resistance, such as proteins: the rise in blood glucose can be delayed to as far as 10-15 hours after the meal, depending on the consumed amount. This explains why I had “perfect” blood glucose during the day, and witnessed it explode and skyrocket during the night.
Past experiences have taught me that an unstable fasting blood glucose is a clear red light pointing at an insulin resistant organism.
To add to the “illusion” of perfect blood glucose, while it is true that it was in an acceptable range for most of the day, I often experienced low blood glucose levels in the hours after my meals. In almost every day of the experiment I reached 60-70 BG levels after lunch and during the entire afternoon, regardless of how much sugars or carbs I ate to make it right. All those proteins (and fats) were taking carbohydrates’ spot in the cells, leaving carbs to accumulate in the blood.
I have been revisiting eh Mastering Diabetes book to understand how all of this works and figure out some explanations, and I have found them:
“When cells in your liver and muscles begin burning and storing fatty acids, […], they block glucose from entering because the cellular machinery required to uptake, process, and store glucose has been deprioritized. In effect, cells in your liver and muscle alter their internal enzymatic machinery based on the fuel that is most readily available. How do these cells block glucose from entering? It’s actually quite simple—they stop paying attention to insulin by downregulating insulin receptors located on the cell surface. Within hours of a single high-fat meal, insulin receptors become less numerous and less functional, perform less work, and have a very difficult time recognizing insulin in your blood. These dysfunctional insulin receptors keep glucose outside of cells, leaving glucose trapped in your blood for long periods of time.”
— Mastering Diabetes: The Revolutionary Method to Reverse Insulin Resistance Permanently in Type 1, Type 1.5, Type 2, Prediabetes, and Gestational Diabetes de Cyrus Khambatta, Robby Barbaro
In fact, this mechanism explains what I have observed during the high-fats AND the high-proteins experiment: in-range/low-ish blood glucose while eating and right after eating, and a steep rise of fasting blood glucose overnight, several hours after the meal. To make this tangible, this is the weekly wrap-up I got from Dexcom.
Effect of high-protein intake on blood glucose: illusion of “good” daily averages, but high variability in truth (red boxes on the top).
The low post-meal levels were compensated by the delayed spikes overnight (yellow area in the graph).
As you can see on the red boxes at the top, the average blood glucose is good (132), but that is merely an illusion of “good” because the standard deviation is very high. That average value is nothing but the result of a constant oscillation between the overnight highs and the afternoon lows. Trading carbohydrates for proteins was not a good idea, and the insulin resistance generated by this shift simply produced the effect that was expected.
I should point out that such irregularities never occurred and never occurs when all my eating is centered on carbohydrates rich foods. A few days after the experiment, once my organism readjusted, my fasting (overnight) blood glucose almost always looked like this:
Overnight blood glucose levels returned to normal, in-range values once I stopped eating high-proteins and returned to whole plant based carbohydrates rich foods.
On the day I took this screenshot, my macronutrients split was
585g carbs,
45g fats and
115g proteins.
Definitely not protein deficient! The difference was that I did not go beyond the ideal threshold of 100-120 grams per day, and I got the bulk of my calories from plant based whole carbohydrates.
Carbohydrates-rich food improved my running (and life) once again
This proved to be beneficial for my running, too, since my BG remained much steadier during workouts, not being exposed to the inevitable irregularities that come from being insulin resistant. Without the fear and the concerns of hitting a low while logging miles on the streets, I enjoyed my runs much more*.
Ultimately, running is a source of joy, and as a diabetic the types of food we eat really do determine whether we’ll be able to experience that joy or we’ll have to surrender to the fact that we can’t run because we are too scared of what our blood glucose will do.
Now that I have tried them all (high-carb, high-fats, high-proteins and even high-junk), I have gathered enough empirical, personal evidence to conclude a carbohydrates rich diet - as long as the carbs are whole and plant based - is by far the best to achieve stable and in-range blood glucose, greater insulin sensitivity, and to enjoy my runs and my life with a big smile and bulletproof health.
* Not to mention all other areas of my life: from focus at work, recovery, sleep, overall energy and mood. All of these improved by just reducing fats and proteins to the recommended amounts and feasting on fruits, whole grains, greens and legumes.
For the more interested reader, here is a very detailed and informative explanation of all things proteins and diabetes. I highly, highly suggest to set out some time to listen!
