Carbohydrates: Foods to Avoid with Chronic Fatigue & Chronic Pain
Dietary carbohydrates often find themselves at the center of nutritional debates, with conflicting information. Carbohydrates are one of the three macronutrients essential for human nutrition, alongside proteins and fats. They serve as the primary energy source for our bodies, fueling cellular functions, supporting physical activity, and powering vital organs like the brain and muscles.
In some corners of the internet, carbohydrates are demonized across the board. Are all carbohydrates bad for health? Should all dietary carbohydrates be avoided for those with chronic fatigue and pain? Absolutely not. There are different types of carbohydrates, and there are many caveats and considerations. Let’s look at some.
There are Different Types of Carbohydrates
Carbohydrates can be broadly classified into three categories:
Simple Carbohydrates: These are composed of one or two sugar molecules and are quickly digested and absorbed into the bloodstream, leading to rapid spikes in blood sugar levels. Foods high in simple carbohydrates include table sugar, honey, syrups, and refined grains.
Complex Carbohydrates: These are composed of multiple sugar molecules linked together, resulting in a slower digestion process and a more sustained release of energy. Foods rich in complex carbohydrates include whole grains, legumes, fruits, and vegetables.
Although fiber is technically a type of carbohydrate, the body does not digest fiber. Instead, it passes through the digestive system, promoting digestive health, regulating bowel movements, and contributing to a feeling of fullness. Fiber-rich foods include fruits, vegetables, nuts, and seeds.
Which Types of Carbohydrates Are Bad for Health?
The carbohydrate most vilified is the simple carbohydrate. These are foods high in sugar and ultra-processed foods. These foods quickly raise blood sugar and can lead to blood sugar swings, which increase fatigue and pain.
The complex carbohydrates may be less problematic for health. Complex carbohydrates do not quickly turn into sugar if that food is also high in fiber. Of the examples listed above, legumes, fruits, and vegetables are very high in fiber, making them rather benign carbohydrates. Whole grains and pasta, on the other hand, are generally quite low in fiber and can lead to blood sugar dysregulation. When I eat too many grains or pasta, I have extreme fatigue due to poor blood sugar balance.
This is the concept of “net carbohydrate,” or the carbohydrate content of a food minus its fiber content. Generally, foods low in net carbohydrates are to be promoted and are less likely to zap energy.
Diets High in Carbohydrates are Promoted by Nutritional Guidelines
National nutritional guidelines suggest carbohydrates make up 45–65% of the total daily caloric intake. That means half or more of your meal plate is composed of foods that are starchy or sweet. Not surprisingly, ultra-processed foods and added sugar are the biggest players in daily carbohydrate intake. After WWII, manufactured food and soda fueled an entire industry of easy carbohydrates. So much so that the average sugar intake is 49 kg per person, per year in the United States, and 35 kg per person, per year in Europe. Compare these statistics to the World Health Organization’s recommendation that individuals consume less than 9.1 kg of sugar per year.
Is it any wonder that this excess of empty calories is driving the rise of metabolic diseases like diabetes? Not just diabetes and overweight, excess sugar consumption is also associated with non-alcoholic fatty liver disease, high blood pressure, cardiovascular disease, macular degeneration, and rheumatoid arthritis.
Not all carbohydrates are bad for health. A zero-carbohydrate diet is impossible. It is virtually impossible to consume zero carbohydrates. Nearly all foods contain dietary carbohydrates. It is far better to reach for carbohydrate-rich foods that are high in fiber. This offsets any ill metabolic effects of carbohydrate foods. It is also important to remember that ATP can be generated from dietary fats—a key principle of the ketogenic diet.
A carbohydrate-laden diet (simple carbohydrates and complex carbohydrates low in fiber) is also not a good idea for post-viral conditions like MECFS, fibromyalgia, and long COVID. The rest of this post will detail the reasons why limiting simple carbohydrates and complex carbohydrates low in fiber should be a top priority for those with these conditions. Here are the reasons why:
Carbohydrates can make you tired & promote brain fog
Carbohydrate handling of the mitochondria is impaired in post-viral conditions
Carbohydrate handling is impaired in those who are sedentary due to changes in the microbiome
Carbohydrates disrupt the HPA axis function
Carbohydrates promote cellular inflammation through AGEs
Some carbohydrates (fructose) zap energy (ATP) production
Carbohydrate Handling is Impaired in ME/CFS
Several studies have measured mitochondrial function in ME/CFS patients. These studies aim to see how effectively or ineffectively mitochondria make energy (ATP) from our food. These studies have shown that oxidative phosphorylation is impaired in ME/CFS. Oxidative phosphorylation is a process that happens inside the mitochondria. The process involves combining oxygen with molecules derived from food, primarily glucose derivatives, to produce energy.
Other metabolism studies have shown that glycolysis is also impaired in ME/CFS. Glycolysis is the process in which glucose (from dietary carbohydrates) is converted into ATP and other substrates. These substrates enter the mitochondria to undergo oxidative phosphorylation. Glycolysis takes place outside of the mitochondria.
While more study is needed, we can gather that using mainly carbohydrates (45–65% of the total daily caloric intake suggested by some guidelines) as the primary fuel is not effective for energy production in those with ME/CFS. Dietary carbohydrates, especially simple sugars and carbs lacking in fiber, will be broken down into glucose. However, glucose in excess will not be effectively processed into ATP via glycolysis or oxidative phosphorylation, given these findings.
With over 10 years of experience creating nutrition plans for patients, I invite you to create your own personalized nutrition plan with me.
Fructose is a Very Problematic Carbohydrate
Fructose is a carbohydrate that is mainly found in fruits, but it is also common in many processed foods to prolong shelf life. The fructose found in fruit is easily handled by the body and never reaches the main portal circulation. This is primarily due to the fiber found in fruits. On the flip side, the high fructose content of processed foods and sweets overwhelms the metabolism and is associated with poor health outcomes.
Unless we’re in a state of starvation, excess fructose is shuttled to a storage product, triglycerides. Excess triglycerides are a main cardiovascular disease risk factor. The metabolism of fructose can also stimulate key enzymes involved in cholesterol synthesis. So excess fructose in the diet, from processed foods and sugar-sweetened beverages, is a driver of cardiovascular disease.
Fructose also drives inflammation by increasing high-sensitivity c-reactive protein (hs-CRP). Hs-CRP levels have been shown to double after just three weeks of daily exposure to sugar-sweetened beverages. Eliminating sugar-sweetened beverages (sodas, juices, and similar) is the first step in reducing inflammation in the body.
Fructose overconsumption reduces cellular energy: ATP. Fructose metabolism pushes the production of ADP to AMP—that’s reducing ATP to a low-energy molecule. This AMP is then converted to the waste products IMP and uric acid. Uric acid excess is associated with gout, and high fructose consumption is strongly linked to gout risk. Uric acid puts extra demand on liver cells to make more fats by blocking key Krebs’ cycle enzymes that stress the mitochondria. ATP depletion can also diminish the production of proteins and create overall mitochondrial dysregulation and dysfunction.
Carbohydrates Promote Advanced Glycation End Products (AGEs)
AGEs are proteins or lipids that become sugar-coated (glycated) when exposed to elevated sugars in the blood. Best studied in diabetics, AGEs are believed to be the main culprit in complications of uncontrolled diabetes such as kidney failure, neuropathy, and blindness. However, AGEs can occur in all individuals with high dietary sugar intakes.
Once these molecules are glycated, they can change how cells work by attaching to specific AGE receptors. These receptors then turn on NF-κB, a key pro-inflammatory factor that raises levels of inflammatory cytokines such as TNF-alpha and IL-6. These receptors are abundant and found on smooth muscle cells, endothelial cells, and certain immune cells.
Carbohydrates are Harder to Handle with Age
As we get older, our ability to metabolize the simple sugar glucose is reduced. This is one of the main reasons diabetes is more likely to develop in older adults. In the brain, the poor handling of glucose may be most dramatic. Glucose uptake by the hippocampus—the main memory center—is severely limited with age.
The Microbiome Helps Handle Dietary Carbohydrates
Studies in exercise science have shown that cardiovascular exercise improves the gut microbiome. Specifically, exercise makes the gut microbiome more diverse. More gut diversity is associated with better health outcomes. Those who regularly exercise also show greater concentrations of butyrate, a potent anti-inflammatory byproduct of microbe metabolism.
The other side of this coin is that a sedentary lifestyle is associated with less microbe diversity. There is also less butyrate production and a shift toward a more pro-inflammatory gut environment. Lack of microbiome diversity has long been established in fibromyalgia, ME/CFS, and more recently in long COVID.
A large study of 8416 participants aged 50–65 used an accelerometer to measure exercise and looked at fecal samples. Those who performed high or moderate-intensity exercise had a more diverse microbiome. There were also more microbe species associated with carbohydrate metabolism. In the sedentary group, there was less microbe diversity and fewer species associated with carbohydrate metabolism.
These findings support the notion that those who are sedentary, such as those with chronic illnesses, have a gut microbiome that is less equipped to handle dietary carbohydrates. In such a case, the answer for us with post-viral conditions is not to exercise to improve microbiome diversity. Instead, a dietary modification that addresses these shortcomings is important to consider! By prioritizing complex carbohydrates high in fiber and minimizing consumption of simple sugars and low-fiber carbohydrates, individuals can better manage their symptoms and improve their quality of life. Remember, the key to success lies in understanding your body's unique needs and making informed dietary choices that support your health and well-being.
References
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Gao Y, et al. (2017) Dietary sugars, not lipids, drive hypothalamic inflammation. Mol Metab. 6(8):897-908.
Lynch, M. A. (2019). Can the emerging field of immunometabolism provide insights into neuroinflammation? Progress in Neurobiology, 101719.
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Baldanzi G, Sayols-Baixeras S, Ekblom-Bak E, et al. Accelerometer-based physical activity is associated with the gut microbiota in 8416 individuals in SCAPIS. EBioMedicine. 2024;100:104989. doi:10.1016/j.ebiom.2024.104989
Clauss M, Gérard P, Mosca A, Leclerc M. Interplay Between Exercise and Gut Microbiome in the Context of Human Health and Performance. Front Nutr. 2021;8:637010. Published 2021 Jun 10. doi:10.3389/fnut.2021.637010
