The NOVA Food Scale: A Guide to Choosing Nutritious Foods for Healthy Hair Growth

The NOVA food-classification system is one of the most widely used frameworks in nutrition research for distinguishing foods according to the nature, purpose and extent of their processing. It is relevant to hair growth because it can help identify whether a diet is built mainly around minimally processed foods that naturally provide protein, essential fats, fibre, vitamins and minerals, or around products that may provide energy without the same nutritional breadth. NOVA does not measure the nutrient value of an individual food, but it offers a useful guide for building a diet capable of supporting follicular energy production, keratin synthesis and tissue repair.

NOVA Group 1: Unprocessed or minimally processed foods

Group 1 foods are whole foods that remain close to their natural form. They may have been washed, peeled, chopped, dried, frozen, pasteurised, fermented or pressed, but these processes do not fundamentally alter the food or add large amounts of sugar, salt, fat, flavourings or industrial additives.

This group includes vegetables, fruit, pulses, whole grains, nuts, seeds, eggs, fish, meat, milk and plain yoghurt. These foods provide the protein, essential fats, carbohydrates, fibre, vitamins, minerals and plant compounds the body uses for energy production, tissue repair, immune function and cell growth.

For hair, Group 1 foods supply the raw materials needed to produce keratin, support rapid follicular cell division, maintain the scalp barrier and generate ATP. They also tend to provide a broader range of nutrients than foods designed mainly for convenience, palatability or shelf life. Group 1 foods should therefore form the foundation of a diet intended to support healthy hair growth.

NOVA Group 2: Processed culinary ingredients

Group 2 includes substances extracted from Group 1 foods or obtained directly from nature and used mainly in cooking. Examples include olive oil, butter, sugar, salt, starches and other culinary fats.

These ingredients are not usually eaten on their own. Their purpose is to help prepare, season or preserve meals built from Group 1 foods. Used appropriately, they can improve flavour, texture and energy density, making nutritious meals easier to prepare and enjoy.

From a hair perspective, some Group 2 ingredients can be useful. Olive oil and other unsaturated fats support cell membranes and help with the absorption of fat-soluble vitamins, while small amounts of salt help maintain fluid and electrolyte balance. 

NOVA Group 3: Processed foods

Group 3 foods are made by combining Group 1 foods with Group 2 ingredients such as salt, oil or sugar. Processing is usually used to improve preservation, flavour or shelf life, but the original food remains recognisable.

Examples include canned vegetables, tinned beans, cheese, traditionally made bread, smoked fish, salted nuts and fruit preserved in syrup. Many of these foods can still contribute valuable protein, fibre, minerals and other nutrients to the diet.

For hair growth, Group 3 foods can be useful and practical, particularly when they make nutritious foods more accessible. Tinned fish can provide protein and omega-3 fats, canned beans can contribute protein, iron and fibre, and cheese can supply protein and calcium. The main consideration is that some processed foods contain higher amounts of salt, sugar or saturated fat..

NOVA Group 4: Ultra-processed foods

Group 4 foods are industrial formulations made largely from refined ingredients, extracted food substances and additives. They often contain combinations of refined starches, sugars, oils, protein isolates, emulsifiers, flavourings, colourings, sweeteners and preservatives that would not normally be used in home cooking.

Examples include many packaged snacks, confectionery, fizzy drinks, instant noodles, sweetened breakfast cereals, mass-produced baked goods, some meal-replacement products and many ready meals.

Ultra-processed foods can provide substantial calories, but they are often lower in fibre and may offer a narrower range of vitamins, minerals and intact food structures than meals based mainly on Group 1 foods. Diets heavily dominated by these products may therefore supply energy without consistently providing the protein quality, essential fats, iron, zinc, folate, magnesium and other nutrients required for follicular growth and repair.

They may also contribute to sharp swings in blood glucose, poorer appetite regulation and an unfavourable metabolic environment when consumed frequently and in large amounts.  The goal is to prevent Group 4 foods from replacing the minimally processed foods that should provide most of the diet’s nutritional value.

How to use the NOVA scale for hair health

The NOVA scale helps reveal the overall structure of the diet by showing how much is built around whole and minimally processed foods versus industrially formulated products. For hair health, it provides a simple way to assess whether most meals are likely to deliver a broad mix of protein, fibre, essential fats, vitamins and minerals needed for follicular growth, energy production and tissue repair.

For healthy hair growth, most meals should be built around Group 1 foods, with Group 2 ingredients used to prepare them and selected Group 3 foods included for convenience and variety. Group 4 foods can still be eaten, but they should not crowd out the foods that provide the follicle with the raw materials it needs to grow.