Carbohydrates and Hair Growth: How Blood Sugar, Fibre and Energy Metabolism Affect Hair Health

Carbohydrates have become nutrition’s favourite villain, the visceral fat origin story. Spme research insists they are essential fuel, whilst other studies say consumption leads to increased weight gain, inflammation and fatigue. The reality is: carbohydrates are not inherently good or bad. What matters is their structure, nutritional quality, degree of processing and the way the body responds to them.

As one of the three main macronutrients, carbohydrates provide glucose, an accessible source of energy for the brain, muscles, liver and rapidly dividing cells, including those within the hair follicle. They also appear in many of the foods that supply fibre, vitamins, minerals and plant compounds. A bowl of lentils and a packet of sweets both contain carbohydrate, but metabolically and nutritionally they have very different profiles.

Simple carbohydrates are not all the same

Simple carbohydrates are made from one or two sugar molecules, which allow them to be digested and absorbed quickly. They include glucose, fructose, sucrose and lactose and are found in table sugar, honey, syrups, fruit, milk and fruit juice.

Whole fruit contains naturally occurring sugar alongside fibre, water, vitamins and plant compounds, which slow digestion and improve the nutritional value of the food. Fruit juice has lost much of that fibre, allowing its sugars to enter the bloodstream more rapidly. Confectionery, sugary drinks and many baked products often provide concentrated blood sugar spike with relatively little protein, fibre or micronutrient value.

A rapid rise in blood glucose prompts the pancreas to release insulin, allowing glucose to move from the bloodstream into cells. This is a normal response. Problems arise when large amounts of rapidly absorbed carbohydrate are consumed repeatedly, particularly without enough fibre, protein or fat to slow absorption. Over time, this pattern contributes to unstable energy fluxes, increased triglycerides, insulin resistance, oxidative stress and inflammatory signalling.

Complex does not automatically mean better

Complex carbohydrates contain longer chains of sugar molecules and include starches and many forms of fibre. They are often described as slower-releasing, but this depends heavily on how the food has been processed.

White bread, white rice and many breakfast cereals contain complex carbohydrate in the form of starch, yet much of their original fibre and structure has been removed. Once digested, they can raise blood glucose quickly because the starch is readily broken down into glucose.

Whole or minimally processed carbohydrate sources behave differently. Beans, lentils, chickpeas, vegetables, whole fruit, oats, barley, potatoes and other root vegetables retain more of their natural fibre and structure. They also provide vitamins, minerals and plant compounds that support digestion, microbial diversity, energy metabolism and tissue repair.

Portion size, preparation method, ripeness and the other foods eaten in the meal all influence the outcome of blood glucose response. A baked potato eaten alone, for example, will behave differently from one served with vegetables, olive oil and a protein source.

What about grains, gluten and phytates?

Whole grains can provide fibre, B vitamins, magnesium, iron and other nutrients, but they also contain phytates, compounds that store phosphorus within seeds and can bind minerals during digestion. Phytates are also present in pulses, nuts and seeds.

The practical significance of phytates depends on the wider diet. Soaking, sprouting, fermenting and cooking can reduce phytate levels, while eating vitamin C-rich foods alongside plant-based iron improves absorption. In a varied and nutritionally adequate diet, whole grains can make a useful contribution rather than acting as nutritional saboteursn.

Gluten is a completely separate issue. It can damage the intestinal lining in people with coeliac disease and may cause symptoms in some people with non-coeliac gluten sensitivity. For those without these specific conditions, there is no good reason to assume that gluten routinely compromises gut integrity. Removing grains unnecessarily may reduce fibre intake and dietary variety without providing a meaningful benefit.

Why do some people feel better eating fewer carbohydrates?

People often report better energy, reduced bloating or easier weight management after reducing carbohydrate intake, but this does not always mean carbohydrate itself was the problem.

A lower-carbohydrate diet often removes sugary drinks, pastries, snack foods, oversized portions of refined starch and other ultra-processed products. Protein and vegetable intake may increase at the same time, making meals more filling and reducing fluctuations in blood glucose. The improvement may therefore come from better food quality and a more balanced meal structure rather than carbohydrate restriction alone.

People with early stages of insulin resistance may benefit from reducing the amount of rapidly absorbed carbohydrate they eat. Those with specific digestive sensitivities may feel better afterremoving grains or fermentable carbohydrate. 

Carbohydrates and the gut microbiome

Many of the carbohydrates the body cannot fully digest become food for the gut microbiome. Fibres and resistant starches reach the colon, where bacteria ferment them and produce short-chain fatty acids such as butyrate, acetate and propionate.

These compounds support the intestinal lining, influence immune regulation and contribute to glucose and lipid metabolism. A carbohydrate intake built around vegetables, pulses, whole fruit and other fibre-rich foods therefore supports more than energy production. It also helps maintain the gut barrier and the microbial ecosystem involved in nutrient handling and inflammatory control.  In contrast, a diet high in refined carbohydrate but low in fibre may supply plenty of glucose while providing relatively little material for beneficial fermentation.

Which carbohydrates are worth eating?

The strongest choices are generally foods that provide carbohydrate alongside fibre and a meaningful range of nutrients. These include vegetables, whole fruit, beans, lentils, chickpeas, root vegetables and appropriately selected whole grains.

Refined carbohydrates such as sugary cereals, pastries, sweets, sweetened drinks and many packaged snacks are better treated as occasional foods. They are easy to consume quickly, often provide limited satiety and can displace foods with greater nutritional value.

Meal composition also matters. Combining carbohydrate with protein, healthy fats and vegetables usually slows digestion and produces a more controlled glucose response. A piece of fruit with nuts or yoghurt, for example, is metabolically different from fruit juice consumed on an empty stomach.

For healthy hair and wider metabolic health, the best carbohydrate sources deliver more than glucose. They also bring fibre, micronutrients and the structural complexity that allows the body to handle that energy well.