Why Going Low Carb Might Be Slowing Your Fat Loss

For Years, We've been Told That Carbs Are the Enemy.

Low-carb diets have dominated weight-loss culture, from Atkins and Keto to "no sugar" challenges, all built on the idea that cutting carbohydrates is the fastest way to burn fat.

But where did this belief come from?

Most of it stemmed from early diet models that have oversimplified how weight management works: "carbs raise insulin, insulin stores fat, therefore carbs make you fat." This perspective doesn't reflect the complexity of human metabolism or the many essential processes in which carbohydrates are involved. 

Its worth noting that carbohydrates include fruit, vegetables and whole grains - some of the most nutrient dense foods available. When we demonise "carbs," we often overlook their role in providing energy and micronutrients that support overall metabolic function.

Overindulging in highly processed carbs (pastries, white bread, crisps) can disrupt dietary balance, just as overconsumption of any macronutrient can. However, carbohydrates in whole-food forms have a valuable role in our diets. 

In this article, we'll explore the physiological role of carbohydrates, what happens in the body when intake is low, and how to strategically include them. The goal is to shift the narrative from restriction to understanding, because when you have a base line understanding of why and how your body uses particular food group, you can finally eat with confidence not confusion.

The science of Energy and Metabolism.

While calories play a part in a weight loss journey, it is also a downstream approach. Metabolism is more than just a numbers game. How your body uses, stores and converts energy from food is influenced by hormones, enzyme activity and cellular energy demands.

In other words, simply eating less may not produce the desired outcome (i.e fat loss) if metabolism has adapted to lower energy availability. Understanding the physiological mechanism behind energy use provides a more compete picture than focusing solely on caloric intake.

How Carbohydrates Fit In.

Carbohydrates provide a readily available source of energy for daily activities and exercise. Tired and craving sweet food? Your body may be signalling the body's need for energy.

Modern diets often feature highly processed carbohydrate sources, which can be over consumed. If you're caught blaming carbohydrate intake on weight gain, there is a simple solution. Choosing whole-food carbohydrates, such as fruit, vegetables and whole grains, ensures the body receives energy and micronutrients to support metabolic function. 

Let's dive into the science of carbohydrate function in the body.

Carbohydrate Biochemistry Explained 

When carbs are chronically low, the body adapts, often in ways that may work against your fat loss goals and heres why:

At the cellular level, mitochondria (the powerhouses of our cells) rely on biochemical pathways, such as the Kreb Cycle, to generate ATP- the energy currency of the cell. Carbohydrate-derived molecules such as oxalocetate, are involved in these processes. Adequate carbohydrate intake supports these pathways, while extremely low intake may influence how efficiently the body metabolises energy from different macronutrients.

In simpler terms: fat burns in the flame of carbohydrate

When carbohydrates are too restricted, the bodys ability to convert fat into useable energy can become less efficient, which may contribute to tiredness, slower recovery or that "sluggish" feeling.

Hormones, Energy and Carbohydrates

Carbohydrates also interact with hormones that influence metabolism:

• Thyroid: Adequate energy and nutrient intake support normal thyroid activity
• Cortisol: glycogen (the body's stored carbohydrate) availability contributes to energy balance and can influence stress hormone regulation
• Insulin: A normal metabolic response to insulin supports nutrient delivery and energy utilisation.

Balanced intake of carbohydrates, protein and fat, together with physical activity, helps the body maintain normal metabolic processes.

How and When to Prioritise Carbs

Timing and context can help optimise energy use:

• Before training: to fuel performance and prevent muscle breakdown
• After training: to replenish glycogen stores and support recovery
• During periods of high activity or stress: to buffer cortisol and maintain energy balance when energy exertion is higher
• From whole food sources: fruits, vegetables, rice, oats all provide the body with micronutrients - the tools to generate energy

The Takeaway

Carbohydrates are not inherently "bad." They are actually super-important, especially if you're an athlete or someone who has a high daily activity level for example. They provide energy and support normal metabolic processes. Extreme restriction is not necessary for effective dietary planing and may influence how efficiently the body uses different energy sources.

Focusing on nutrient-dense carbohydrates and supporting your intake with foods that provide essential vitamins and minerals, allows you to make informed, evidence-based dietary choices.

Fuel smart. Move often. Eat with confidence knowing your body was designed to use food, not fear it.

This information is for educational purposes only and is not intended to diagnose, treat, cure of prevent any disease. It should not be taken as individual medical or nutritional advice. Always seek the guidance of a qualified healthcare professional before making changes to your diet, supplement routine or lifestyle.

About the Author

Emily is a Clinical Nutritionist (BHSc) passionate about metabolic health—how your body creates and uses energy...

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