Some Problems with Too Low Carb
Although I do believe in eating moderately low carb, I do not believe in a zero carb diet. That is just too low. And in this article, I'll point out some problems that have been reported when carbohydrate intake is too low for an individual's metabolism.
I have nothing against low carb diets. In fact I think low carb diets are in general a good healthy diet for most people. However, it may not be right for some individuals if they go too low. Each individual have a different level of carbohydrate tolerance. Some people can eat moderate amounts of carbs without ill effects. But some carb sensitive individuals or individual with type 2 diabetes may need to limit carbs severely.
Humans have adaptation for carbohydrate consumption
In the below video, Chris Masterjohn says that all humans have genetic adaptations for processing carbohydrates. However, depending on the number of salivary amylase, some individuals can genetically handle starch better than other individuals. And the variance is large from one person to the next. Individuals with greater number of salivary amylase can generally tolerate carbs better.
Okay, with such a large portion of the population over-consuming sugar, you would be surprise that there is such a thing a glucose deficiency. But there are such reports. While it is true, that most people would not even come close to having a glucose deficiency. There are a few rare reports of symptoms of glucose deficiency when individuals went too low on carbs or went on a zero carb diet.
Paul Jaminet writes about the Dangers of Zero-Carbs in a series of articles and how it can lead to vitamin C deficiency. From what I've gather from his article, this is how it works.
Carbs is needed to stimulate production of insulin, which is needed to stimulate the GLUT transporters of the cells, which brings DHAA into the mitochondria of the cells so that it can be recycled back to vitamin C by glutathione. And so, without carbs, this vitamin C does not get recycled as efficiently. To make matter worst, glutathione itself is recycled by a selenium-dependent enzyme. And low-carb diets tend to deplete selenium.
Paul concludes by writing ...
"Zero-carb dieters are at high risk for vitamin C deficiency, glutathione deficiency, and selenium deficiency. Anyone on a zero-carb diet should remedy these by supplementation. These deficiencies are exacerbated by chronically low insulin levels."
In other post, he also talks about how zero-carb is associated with increased kidney stones.
He believes glucose as a nutrient, and as such having too much as well as having too little is a bad thing. In another article, he writes of the link between a zero carb diet and increase risk of gastrointestinal cancers and inability to produce mucus. So dry eyes and low mucus can be a sign of glucose deficiency.
Bio-hacker Dave Asprey in his podcast mentioned that when he went on a zero carb diet for a few months, he experienced dry eyes and got a few additional food sensitivities due to lack of mucus in the intestinal linings. After his zero carb experiments, he writes more about how it gave him poor sleep, low thyroid function, and higher LDL cholesterol.
High LDL Cholesterol When Too Low Carb
Dr. Cate Shanahan, whose post on her site mentions that going low-carb too quickly can decrease thyroid function.
When thyroid function decreases, the LDL receptors are slow to take up LDL cholesterol. And this may cause LDL cholesterol to go up on a very low carb diet.
High Blood Glucose with too low carbs
Dr. Sears of the Zone Diet explains in the below video why having too few carbs may raise blood glucose levels.
Too few carbs results in an glucose deficiency. When the brain needs glucose to function, the body breaks down muscle mass to produce the glucose in a process known as glucose-neogenesis. Also the adrenal glands starts producing more cortisol as a stress response. This causes a slight insulin resistance in the muscles to prevent the muscles from taking up all the few available glucose in order to spare the glucose for the brain.
The article "Insulin Insufficiency and a Low Carb Diet" writes ...
"A low carb diet causes insulin levels to fall quickly. ... If you have insulin insufficiency due to a hereditary defect or severely reduced number of beta cells, a low carb diet can cause your glucose levels to skyrocket."
Too Low Carb May Also induce insulin resistance
Mark's Daily Apple writes that ...
"...going very low carb – to around or below 10% of calories, or full-blown ketogenic – can induce ”physiological” insulin resistance. Physiological insulin resistance is an adaptation, a normal biological reaction to a lack of dietary glucose. ... the brain must have glucose. It can use ketones and lactate quite effectively, thus reducing the glucose requirement, but at the end of the day it still requires a portion of glucose."
The HyperLipid blog also talked about physiological insulin resistance.
Again, this is an glucose deficiency. While Ron Rosedale may say that many of problems of low carb is due to the fact that one has not adapted to "fat-burning" mode and is still in "glucose burning" mode. There may be some people who can not easily switch to "fat-burning" mode. Or that they are unable to consume enough fat for the brain to meet its needs.
Addition of Safe Starches
So what kinds of carbs do we eat. No, not pizza, bread, and pasta. The carbs that we should be eating are vegetables, fruits, and safe starches. Safe starches are foods such as rice, yams, sweet potatoes, potatoes, and taro.
Paul Jaminet's Perfect Health Diet is based off of the Paleo Diet with the addition of safe starches. Both diet advocates the consumption of vegetables.
The Perfect Health diet includes the addition of white rice, which the Paleo Diet excludes because it is a grain. Despite advocating safe starches, The Perfect Health Diet is still considered low to moderate carbs -- or at least lower carb than the typical American diet.
There is some lively debates about "safe starches" which you can follow here on Jimmy Moore's post. And you can watch a panel debate about safe starches at the Ancestral Health Symposium (video below)...
In the panel, on one end of the spectrum is Paul Jaminet who advocates safe starches. And on the other end of the spectrum is Ron Rosedale who does not believe in consuming any starches. Jimmy Moore is moderator.
Adding White Rice and Potatoes as safe starches
White rice is considered a safe starch because its bran (where most of the antinutrients are) have been stripped. So it is mainly starch.
However, some people can be sensitive to potatoes. Potatoes are a gluten-cross reactive food. That means that if you are sensitive to gluten, you may also be sensitive to potatoes and other gluten-cross reactive foods without knowing it. Cyrex Labs has a test for that.
Potatoes are in the nightshade family, while sweet potatoes and yams are not. Nightshades are one class of food that people can be sensitive too. They are sometimes avoided by those with autoimmune conditions.
WHFoods.com writes that "Unlike potatoes, sweet potatoes do not contain nightshade alkaloids" and that ...
"Nightshade plants contain a variety of substances called alkaloids, and these substances can sometimes provoke allergy-related symptoms. The nightshade alkaloids are completely avoided with a change from baking potatoes to sweet potatoes because sweet potatoes are not part of the nightshade family. "
So in terms of safe starches, sweet potatoes and yams are safer than the white baking potatoes.
Amount of Carbs Needed is Different for Everyone
Since the amount of carbs needed is different for everyone and eating too much carb and eating too little carb is a bad thing, how are we to determine how much carbs to eat.
Get a glucometer and measure your blood sugar before meal, 1 hour after meal, and 2 hour after meal. If reading is normal before a meal, then likely you the meal you are about to eat can have a little more carb and you will still be safe. If reading 1 hour after and 2 hours after eating is spiking too high, then you know that you have just ate too much carb for your metabolism. As to what is considered too high of blood glucose, I refer your to chart in ChrisKresser.com.