Macronutrients & micronutrients explained

Reviewed by our clinical team

Trying to eat a healthier diet can feel like a huge challenge. If you’re doing it for the first time, you might find yourself overwhelmed by all the different advice and complicated terms.

Two popular terms used when talking about nutrition are “macronutrients” and “micronutrients”. Though these words may be intimidating, the definitions are actually pretty simple – which means your new diet can be too.

What are macronutrients?

There are three macronutrients (‘big’ nutrients): carbohydrate, protein, and fat. These are the nutrients we need to eat in the greatest quantities.

• We need carbohydrates because they are our main source of energy.
• We need protein for growth and repair, and general good health.
• We need fat because it contains essential fatty acids that our bodies can’t make. It also helps us to absorb the important fat-soluble vitamins A,D,E and K.

Individual foods tend to mostly be made up of one type of macronutrient, with smaller amounts of the other two. Some foods will have an even split – cheese, for instance, is made up of fat and protein in fairly equal amounts, with much smaller amounts of carbohydrate.

How much of each macronutrient should I eat each day?

The NHS offers daily reference intakes which can be used as a very general guide:

• Less than 70g total fat  
• 260g of carbohydrate  
• 50g of protein

What’s most important, however, is making sure that we eat the right types of foods, and in the right portion sizes. According to the NHS Eatwell Guide, our daily diet should look like this:

• Over 1/3 fruits and vegetables  
• Over 1/3 high-fibre starchy foods  
• Some healthy protein  
• A small amount of dairy  
• Limited amounts of salt, sugar, and saturated fats

In total, men should aim to eat around 2,500 calories each day, and women should aim to eat around 2,000. However, you may need more or less depending on your size and how active you are.

If you stick to these recommendations, you should end up consuming all the macronutrients (and micronutrients) that you need.

Macronutrient source

Carbohydrate

There are three types of carbohydrate: starch, fibre, and sugar. Starch and fibre are really important for our diet, as starch provides us with energy, and fibre helps with digestion and makes us feel fuller. Sugar is less important and should be consumed in much smaller amounts.

The healthiest carbohydrates tend to combine starch and fibre. These foods should feature in your diet as much as possible – remember, the NHS recommends that they fill more than a third of your plate:

• Potatoes with the skins on 
• Wholegrain breads  
• Whole porridge oats 
• Brown rice 
• Wholewheat pasta 
• Starchy vegetables like parsnips, beetroot, and sweet potatoes 
• Pulses like lentils, beans, and peas

All carbohydrates contain natural sugars, but they are still considered healthy.

However, any foods that contain “free sugars” (e.g. added sugar) should be eaten in much smaller quantities. This includes ice cream, biscuits, chocolate, sweets, fizzy drinks, and cakes. The sugars in unsweetened fruit juices, and natural syrups like honey are also considered “free sugars” even though they occur naturally.

In total, adults should have no more than 30g of “free sugars” each day – that’s about seven sugar cubes.

Find out more about healthy alternatives to some of your favourite sugary snacks. 

Protein

Protein is found in red meat, poultry, game, fish, and seafood, as well as animal products like eggs, milk, cheese, yoghurt, and cream. Excellent plant based sources of protein are pulses like lentils, peas, beans, bean sprouts, soya products like tofu, as well as nuts and seeds.

The NHS recommends that the average person needs around 50g of protein each day – this is not very much when you consider that a single chicken breast can contain over 30g of protein.

When adding protein to your diet, aim for the following:

• Eat more pulses like lentils, beans, and peas 
• Have at least two portions of fish each week, one of which is oily (e.g. salmon or mackerel) 
• Choose lean rather than fatty meats (e.g. 5% fat mince, rather than 20% fat) 
• Avoid eating too much red meat or processed meat (e.g. bacon, ham and sausages) 
• Opt for low-fat, rather than full-fat dairy

When preparing your protein, it’s also a good idea to cook it without adding too much fat. For instance, eggs are best eaten boiled or poached, rather than fried or scrambled with a lot of oil or butter.

Fat

The NHS recommends following a low-fat diet, but this doesn’t mean you should have zero fat! Instead, try to eat foods that are healthy sources of fat, such as:

• Vegetable oils 
• Nuts and seeds 
• Oily fish 
• Avocadoes

Unhealthy sources of fat usually come from animal products. They’re high in saturated fat, examples include:

• Fatty cuts of meat 
• Processed meat like sausages 
• Butter 
• Cheese 
• Cream 
• Chocolate, biscuits, cakes, and pastries

The NHS recommends eating less than 70g fat each day, and – within that amount – less than 20g of saturated fat.

What are micronutrients?

Micronutrients are vitamins and minerals such as iron or calcium. They’re essential to our diet in the same way as carbohydrate, protein, and fat are – but we need them in much smaller quantities. 

The good news is that micronutrients are usually contained in the macronutrient-rich foods that make up our diet.

How much of each micronutrient should I eat each day?

There’s a long list of micronutrients that we need in our diet, including:  

• Vitamins A, C, D, E and K 
• Vitamins from the B group including Vitamin B12 
• Folate 
• Calcium 
• Iron

We need very small amounts of each of these micronutrients – so small, in fact that the dosage is normally measured in milligrams (1/1000 of a gram) or micrograms (1/1,000,000 of a gram). The NHS recommends, for example, that we need just 40mg of vitamin C, and 700mg of calcium each day.

Eating a healthy, varied, and balanced diet should deliver all the micronutrients you need. However, if you’d like a full rundown of recommended dosages, you can consult this guide from the NHS.

Micronutrient sources

Micronutrients are found in all kinds of foods, including vegetables, fruits, oily fish, eggs, pulses, and meat. If you eat animal products, always get your five-a-day, and don’t have any big dietary restrictions or serious food allergies, you shouldn’t have any trouble getting all the micronutrients you need.

If you’re on any kind of restricted diet that cuts out whole food groups, you may find it harder. People who follow a vegan diet, for instance, sometimes find it hard to get enough vitamin B12, calcium, and iron. This is why it’s important to speak to your GP before changing to a vegan or any other type of diet. 

Supplements

Micronutrients are best consumed as part of your diet. If you eat a varied, preferably home cooked diet that includes fresh fruit and vegetables you should not need any supplements. In the case of vitamin D though (which our bodies generate through sun exposure) the NHS recommends taking a supplement during the winter and spring, particularly if you live further north.

Get help with your weight loss journey from Online Doctor

If you’re changing up your diet to try and lose weight, Online Doctor can help. We can prescribe Xenical or Orlistat, an NHS-approved weight loss treatment that reduces that amount of dietary fat digested by your body. There are also other weight loss treatments, like, Mounjaro®, Wegovy® and Saxenda®, which might be suitable. Read our guide to weight loss treatments to find out more. 

References

https://www.bhf.org.uk/informationsupport/heart-matters-magazine/nutrition/ask-the-expert/macronutrients
https://assets.publishing.service.gov.uk/Eatwell_guide_colour.pdf
https://www.nhs.uk/live-well/eat-well/
https://www.nhs.uk/live-well/eat-well/different-fats-nutrition/
https://www.nhs.uk/live-well/eat-well/what-are-reference-intakes-on-food-labels/
https://www.nhs.uk/live-well/eat-well/the-eatwell-guide/
https://www.nhs.uk/live-well/healthy-weight/understanding-calories/
https://www.nhs.uk/live-well/eat-well/how-does-sugar-in-our-diet-affect-our-health/
https://www.tesco.com/groceries/en-GB/products/292284222
https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-c/
https://www.nhs.uk/conditions/vitamins-and-minerals/calcium/
https://www.nhs.uk/live-well/eat-well/the-vegan-diet/
https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/