Lesson # 2 - Limiting This Might Actually Be Harmful
to Your Health (and longevity?)
(This is approximately a 4.5 min read)
Over the past couple of decades, the idea that carbs or sugar “are bad for you” has become very popular, to the point that many people decided to follow a low carb or ketogenic diet (consuming less than 50g of carbohydrates per day). Many say they feel great on those diets. However, does that mean that carbs and sugar are “bad for you” as a rule of thumb?
At the risk of sounding blasphemous to some, I would go as far as to say that, in the long run, a low carb diet could actually be harmful.
Consider this: In general, do the people who live the longest and healthiest follow a low carb diet?
in the last newsletter, I showed a couple of graphs that revealed a decline in carbohydrate and sugar consumption during time periods marked by rising chronic disease, a fact that may cast doubt on a relationship between carbs and disease.
The five areas in the world known as “blue zones” are places where there are a disproportionate number of centenarians, people who live to 100 and beyond, and where older people tend to be healthier than others living in most of the Western world. These are specific towns or regions in the US, Costa Rica, Greece, Italy, and Japan, as shown in the image below.
The diet of the people who live there is certainly not devoid of carbohydrates and sugar - at least natural sources of sugar.
In order to understand why sugar and carbs aren’t necessarily “bad for you,” it is helpful to learn what they are and what role they play in human health.
What are sugar and carbohydrates?
Sugar is, by definition, any of the class of soluble, crystalline, typically sweet-tasting carbohydrates found in living tissues and exemplified by glucose, fructose, and sucrose.
Here is a how a molecule of glucose is drawn in science publications.
You find sugar mostly in sweeteners like table sugar (aka sucrose, derived from sugar cane or beets), as well as in honey, maple syrup, agave, and fruit.
Carbohydrates are primarily one of two things
- Sugar
- Any larger structure made of multiple joined sugar molecules, like starch or fiber.
Starch is the most common type of dietary carbohydrate. It consists of chains of glucose molecules, as depicted in this image:
Common sources of starch include baked goods or cooked grains made from wheat, rye, rice, corn, as well as root vegetables, legumes and pulses (beans and lentils).
Fiber is also considered a carbohydrate, but it is not digestible, meaning it is not absorbed by our digestive system into the bloodstream.
What is the function of sugar and carbohydrates?
Glucose, the most important and common molecule in the sugar and carbs category, constitutes “fuel” for the cells of the body. In other words, it is a source of energy for the cells of the human body. That energy allows the cells to perform their various functions.
This formula, commonly seen in biochemistry textbooks, is a depiction of a summary of how energy is made in the cells. Oxygen and glucose react with one another to form energy, while, in the process, the atoms in these two molecules are rearranged to form water and carbon dioxide.
The diagram below shows all the various steps involved in energy generation that the formula above summarizes. Glucose is broken down and modified to pyruvate, Acetyl CoA, and other molecules. Each step requires “helper” molecules, including vitamins, which are also needed to support the production of energy. Metabolic energy is stored in a molecule called ATP (see diagram), much in the way the electric energy can be stored in batteries.
How important is glucose?
The diagram also shows that along with glucose, fatty acids can be used up to produce energy. However, what isn’t shown here is that fatty acids, especially PUFA, don’t burn “cleanly,” and don’t produce energy as efficiently.
Certain cells. Specifically, red blood cells), rely exclusively on glucose, while others are heavily dependent on glucose, like brain and nervous system cells. Those cells can’t utilize fatty acids at all. Other cells, like those that make up certain glands, including (paradoxically) the pancreas, prefer to “burn” glucose over fat.
In the average sized person, red blood cells need 30 grams of glucose a day, and the brain and nervous system needs about 120 grams.
It is true, as I stated earlier, that often those who follow a low carb diet feel well. They report feeling energetic and having clarity of mind and often report weight loss.
If red blood cells and the brain are heavily dependent on glucose, then how does it not bother those who follow a very low carb, ketogenic diet? Well, some glucose is produced from and supplied by the amino acids that make the protein in muscles, and, to some extent, that glucose helps to nourish red blood cells and the brain. The rest of the fuel for the brain and nervous system cells comes from ketones. These are molecules made from fatty acids, only occurring when glucose is absent from the diet. So, while fatty acids can not nourish the brain cells directly, under glucose deprivation, some fatty acids make ketones, which can nourish the brain.
However, producing glucose and ketones from within occurs solely as an adaptive response to glucose deprivation. In my understanding, based on my readings and interactions with some of those who opted for a low carb diet, the benefits tend to be short-lived, lasting from weeks to months. Also, many people find it difficult to adhere to a low carb diet.
Are sugar and carbs to blame for chronic diseases?
I often hear or read various sources that asset that sugar can cause diabetes, make people fat, suppress immunity, and cause cancer. However, there are studies in the medical literature that completely refute such assertions.
When it comes to diabetes, other factors, such as stress, PUFA, obesity and something called endotoxins (which I will speak about at a later lesson) are far more scientifically - supported culprits.
When it comes to weight gain, in one study, post-menopausal women who were instructed to eat carbs and protein to satiety, but kept fat intake low, experienced weight loss. (See reference below).
As for immunity, when lymphocytes (a type of immune cell) become activated (as when they need to fight an infection), they turn on their glucose uptake and decrease their fatty acid intake (meaning they prefer burning glucose for energy).
As for the assertion that sugar feeds cancer, it is known that fat is the preferred source of fuel of cancer cells.
I already mentioned that blue zones dwellers don’t follow low-carb diets.
Having said that, they also don’t eat much-processed food, such as chips, doughnuts, and cookies. Not only are these types of food devoid of the vitamins and minerals needed to assist in the extraction of energy from glucose, but they are also typically made with vegetable oil (PUFA). As I stated in the last lesson, PUFA makes it harder for cells to utilize glucose to produce the energy required for good health.
Blue zone dwellers don’t eat much PUFA. As for carbs, they tend to eat fresh fruit, some raw vegetables, as well as cooked root vegetables and cooked grains. Perhaps, it will be helpful to emulate these aspects of blue zone dwellers to achieve health and longevity.
Ripe fruit provides easy to digest carbohydrates combined with naturally occurring vitamins and minerals, helping to extract energy from glucose.
Root vegetables also provide a number of important minerals. Blue dwellers don’t eat a lot of raw vegetables. Even though raw vegetables provide important micronutrients, the relatively high amount of fiber limits the digestibility and availability of these nutrients. While we learn that fiber is important for gut health, it may actually present a source of trouble for some people dealing with chronic diseases. I will expand on this at a later lesson.
In summary, so far you learned that you should limit PUFA and that carbs aren’t the root of all evil, but that ripe fruit, cooked root vegetables, and grains (with some discernment) may present healthy choices of carbohydrates.
I hope my explanations as to why there is no need to be afraid of healthy sources of carbs and sugar make sense to you. Feel free to state your thoughts or questions in the comments section below. Let me know how this may apply to you.
In the next lesson, I will reveal another common culprit of chronic disease and premature aging that is hardly spoken about.
