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Are Carbs Bad for You? The Truth About Low-Carb & Keto Diets

For years, carbohydrates have been demonized as the culprit behind weight gain and various health woes. This has led to the rise of low-carb and ketogenic diets promising rapid weight loss and improved health. But before you banish carbs from your plate entirely, let’s explore a more nuanced approach. While carbs are typically considered essential for healthy bodily function, there are some benefits (and risks) associated with reducing your carb intake. In this article, we will discuss the role of carbohydrates, the potential benefits and drawbacks of the keto diet, and ultimately, help you discover your ideal carb balance for a healthy and sustainable lifestyle.

a bowl of healthy food

The Importance of Carbohydrates

While some weight loss fanatics would have you believe that carbs are the enemy, they actually play a very important role in the body. Here are the key areas that carbs influence:


Energy Source

Carbohydrates are the body’s preferred source of energy. During digestion, complex carbohydrates (starches) and simple carbohydrates (sugars) are broken down into glucose, a type of sugar that fuels cells throughout your body. This readily available energy is crucial for daily activities, from thinking clearly to performing physical tasks.

Brain Function

The brain relies on glucose almost exclusively for energy. Without sufficient carbohydrates, mental function can decline, leading to feelings of fatigue, difficulty concentrating, and irritability.

Digestive Health

Fiber, a type of complex carbohydrate found in foods like vegetables and whole grains, plays a vital role in digestion. It promotes regularity, helps maintain a healthy gut microbiome, and may even reduce the risk of certain chronic diseases like type 2 diabetes and heart disease.

Weight Management

While often demonized for weight gain, some carbohydrates, particularly those high in fiber, can actually aid in weight management. Fiber-rich foods tend to be more filling and keep you feeling satisfied for longer, potentially helping to control appetite and reduce overall calorie intake.

Athletic Performance

Athletes in particular rely heavily on carbohydrates stored as glycogen in the muscles and the liver for quick energy bursts during high-intensity exercise and endurance activities. Replenishing glycogen stores after exercise with carbohydrate-rich foods is essential for recovery and maintaining peak performance.

The type and amount of carbohydrates you consume matters. Simple carbohydrates found in sugary drinks, processed foods, and refined grains can cause blood sugar spikes and crashes, leading to energy dips, cravings, and potential weight gain. In contrast, complex carbohydrates found in whole grains, fruits, vegetables, and legumes provide sustained energy, essential vitamins, minerals, and fiber.


Low-Carb Diet vs Keto Diet

Low-carb and keto diets both aim to reduce the amount of carbohydrates you consume to a degree however, the ketogenic diet (keto) takes it a step further, aiming to shift the body’s primary fuel source from glucose (derived from carbohydrates) to ketones produced in a metabolic state called ketosis. Keto diets drastically restrict carbohydrates and emphasize high fat intake and moderate protein intake – with the diet often consisting of 70-80% fat, 10-20% protein, and only 5-10% carbohydrates.

Low-carb diets on the other hand typically allow for a moderate intake of carbohydrates, focusing on whole grains, fruits, and vegetables. Low-carb diets do not attempt to put the body into ketosis, but rather restrict carbohydrate intake by choosing limited portions of nutrient-dense foods.


What is Ketosis?

Ketosis is a metabolic state in which the body burns fat for fuel instead of carbohydrates - its usual energy source. Ketosis happens when carbohydrate intake is significantly reduced, causing the liver to convert fat into fatty acids and ketone bodies. The ketone bodies then serve as an alternative energy source for the brain and other parts of the body. 


What is Keto Flu?

Because carbohydrates play such important roles in the body, their drastic reduction can lead to side effects, especially during the initial stages of the diet. The “keto flu” is characterized by fatigue, headache, nausea, and irritability. These symptoms are explained by the following side effects of extreme carb restriction.


Risks & Side Effects of the Keto Diet

Eliminating or drastically reducing your carbohydrate intake comes with some significant risks and potential side effects.

  1. Nutritional Deficiencies: Removing carbohydrates can lead to a lack of vital nutrients as the diet restricts the intake of fruits, vegetables, and whole grains which provide essential sources of vitamins, minerals, and fiber.

  2. Decreased Energy & Performance: Since carbohydrates are the primary energy source for the body, removing them can result in decreased energy levels, which may impact daily activities and physical performance.

  3. Mood Changes: Carbohydrates have a role in the production of serotonin, a neurotransmitter that helps regulate mood, appetite, and sleep. Sudden elimination of carbohydrates can affect serotonin production and may lead to mood swings and irritability.

  4. Ketosis: In the absence of sufficient carbohydrates, the body enters a state called ketosis, where it starts to burn fat for energy. This can lead to symptoms like headache, fatigue, dizziness, and nausea.


Proposed Benefits of the Keto Diet

The long-term safety and efficacy of the keto diet has not yet been thoroughly studied. Consult a doctor or nutritionist before making any significant changes to your diet.

  1. Weight Loss: Many people adopt the keto diet for weight loss. Since the body is using fat as its primary energy source, it can lead to rapid weight loss. Additionally, ketosis can decrease hunger and appetite, which helps reduce overall calorie intake. 

  2. Blood Sugar Control: The keto diet can help stabilize blood sugar levels, which is beneficial for individuals with type 2 diabetes or those looking to manage their blood sugar more effectively. 

  3. Increased Mental Focus: Some proponents of the keto diet report improved clarity and mental focus. This is thought to be due to the steady supply of energy (ketones) to the brain, which avoids the spikes and dips associated with fluctuating glucose levels. 

  4. Therapeutic Uses: Originally developed to help treat neurological diseases such as epilepsy, the keto diet has been found to reduce the frequency of seizures in epileptic patients, particularly children who do not respond to conventional treatment. 


A Balanced Approach

While the keto diet can offer several benefits, it's not suitable for everyone. When choosing a diet to adhere to, the focus should be on your individual health goals, dietary preferences, lifestyle, and medical considerations. If you choose to explore the keto diet, it is important to approach it with careful planning and consideration of your unique health needs. For many, achieving a balanced diet that includes carbohydrates, fats, and proteins will be more sustainable and beneficial in the long term. 


Scott Ryan, CSCS, *RSCC, CF-L1, CF-W, BFRC, Director- Fit Societe

A professional coach who specializes in Applied Functional Science, Strength and Conditioning, CrossFit L1, and Olympic Lifting. He attended New England College in New Hampshire obtaining a bachelor's degree in Kinesiology with an emphasis on Biomechanics. He has a passion for injury prevention and coaching, as he was a collegiate athlete who suffered sports injuries. His goal is to get athletes back to optimal shape as well as prevent future injuries.

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