Aside from the culinary enjoyment it offers, the main purpose of food is to provide energy and nutrients for your body. However, carbohydrate-rich foods can cause fatigue because they trigger insulin spikes and blood sugar “crashes.” Food allergies or intolerances can deplete your immune system and leave you feeling wiped out. Furthermore, certain compounds in food can either cause sleepiness or disrupt your sleep cycle, which leads to fatigue.
Fatigue is usually described as excessive tiredness or a complete lack of energy. There are many causes of fatigue including overexertion, sleep deprivation, debilitating diseases, hormone imbalance, physical injuries, emotional trauma, stress and certain medications. An often overlooked cause of short-term and chronic fatigue is diet and how your body responds to food. If your fatigue becomes a daily issue for many months, you may be diagnosed with chronic fatigue syndrome, or CFS. In addition to extreme exhaustion, other symptoms commonly associated with CFS include muscle pain, achy joints, headaches, confusion, difficulty concentrating, irritability, depression and poor immune response.
Sugary and Starchy Carbohydrates
Sweet fruits, white bread, pasta, white rice, potatoes, ice cream, cookies, desserts and sweets are all carbohydrate-rich. Depending on how much you eat and how quickly the complex sugars are metabolized by your body -- a process represented by the glycemic index -- foods rich in carbohydrates can greatly impact insulin release. For example, white bread has a high glycemic index because it’s quickly digested into glucose and absorbed into your bloodstream, where it triggers insulin release. Eating too much white bread results in big insulin spikes, which removes too much glucose from your blood and leaves you feeling fatigued and without energy.
Allergies and Intolerances
Food allergies and intolerances are relatively common, especially in children. Almost any food can trigger allergies, but about 90 percent of cases are triggered by dairy products, eggs, fish, shellfish, peanuts, tree nuts, wheat or soybeans. Food additives such as preservatives, colorings, artificial flavors and sweeteners can also trigger negative reactions. The most common symptoms of allergic reactions are severe congestion, swelling and breathing problems, although fatigue is not unusual due to an overworked immune system. Mild food intolerances can certainly lead to fatigue over time because of the toll they take on the body.
Tryptophan is an amino acid found in many meats, but particularly chicken and turkey. Tryptophan crosses the blood-brain barrier and is converted to serotonin – a neurotransmitter that’s an important initiator of sleep. As you may have experienced, eating too much turkey during the holidays can leave you feeling sleepy and fatigued due to the sedative effects of tryptophan. Other foods containing lots of tryptophan include soybeans, tuna, salmon and lamb.
Contrary to popular belief, caffeine doesn’t provide energy boosts. It does increase the firing rate of neurons in your brain, which causes your thoughts to race and sleepiness to dissipate, but chronic consumption of caffeine is actually linked to fatigue. Caffeine causes fatigue due to sleep disruption such as insomnia and adrenal gland overstimulation and exhaustion. Foods that contain caffeine are scarce, but any made from dark chocolate high in cocoa are the main culprits.
- Textbook of Functional Medicine; David S. Jones
- Human Metabolism: Functional Diversity and Integration; J. Ramsey Bronk
- Public Health Nutrition: From Principles to Practice; Mark Lawrence and Tony Worsley
- Human Biochemistry; Charles Dreiling
Sirah Dubois is currently a PhD student in food science after having completed her master's degree in nutrition at the University of Alberta. She has worked in private practice as a dietitian in Edmonton, Canada and her nutrition-related articles have appeared in The Edmonton Journal newspaper.