Understanding Macronutrients: Carbs, Fats & Protein Demystified

Balanced plate with all the macronutrients: carbohydrate, protein and fat

What are macronutrients?

In our quest for a healthier lifestyle, understanding macronutrients is crucial.

Protein, carbohydrates, and fats are all macronutrients (nutrients that form a large part of our diet) in our diet, and are the building blocks of our food intake, each playing a unique role in keeping our bodies running smoothly.

Let’s demystify these macronutrients and discover how they contribute to our well-being and a healthy balanced diet.

These essential components of your diet hold the keys to a healthier and more vibrant you.

Balanced plate with all the macronutrients: carbohydrate, protein and fat
Balanced plate with all the macronutrients: carbohydrate, protein and fat

The latest on Carbohydrates why do we need them?

Image of carbohydrates as one of the macronutrients

Pasta in various forms provides us with the macronutrient carbohydrate

Carbohydrates, or “carbs”, are seemingly the enemy…or so we have been led to believe. 

We are surrounded by self-proclaimed nutrition “experts” who have come into the limelight often promoting their version of fad eating plans. 

There are a lot of myths concerning carbohydrates and this will hopefully help you to distinguish the facts from the fiction.  
Carbohydrates, as a macronutrient, cover a broad category of food and not all carbs are the same.

Types of carbohydrates

Carbohydrates are one of three macronutrients found in food – the others being fat and protein.

Hardly any foods contain only one nutrient and most are a combination of the macronutrients, carbohydrates, fats and proteins, in varying amounts.

There are three different types of carbohydrate: sugar, starch and fibre

SUGAR

Sugar is found naturally in some foods, including fruit, fruit juices, milk (lactose) and vegetables. Other forms of sugar (free sugars) can be added to food and drink such as sweets, chocolates, biscuits and soft drinks during manufacturing, or added when cooking or baking at home. In the UK the maximum amount of free sugars (that is, the added sugars) should be 5% of the total daily energy intake or around 7tsp of sugar.

Starch

Starch is made up of many sugar units bonded together. It is found in foods that come from plants. Starchy foods, such as bread, rice, potatoes and pasta, provide a slow and steady release of energy throughout the day.

Fibre

Fibre is essential to maintain a healthy digestive tract and to keep food moving through and eventually passing out of our guts.  A high fibre intake is associated with lower incidence of type 2 diabetes, heart disease and bowel cancer.  We need 30g of fibre per day, but in the UK on average we only have around 18g.  Wholegrains are a really important source of fibre.  An easy way to get more fibre into your diet on a daily basis is to swap your white bread, pasta and rice for whole-grain versions.  

How carbs affect the body

Carbohydrate should be the body’s main source of energy (around 40-50% of energy intake) in a healthy balanced diet.  Carbs are broken down into glucose (sugar) before being absorbed into the bloodstream.

From there, the glucose enters the body’s cells with the help of insulin, released from your pancreas.  Your body uses glucose for energy to fuel all of your activities; whether going for a run or breathing.

Unused glucose can be converted to glycogen found in the liver and muscles. If unused, glucose can be converted to fat, for longer-term storage of energy.

Some carbohydrate is stored in the body, however there is a limited supply, and when you exercise these stores are depleted.

The best way to replenish the carb stores is to eat a carbohydrate rich snack or meal as soon as possible after finishing exercise.  This should also contain some protein as this helps to replenish the stores more quickly.

So, for example, you may choose breakfast cereal with milk, a yoghurt or fruit smoothie, or a stir-fry with rice or noodles.  A diet too low in carbs can lead to a lack of energy during exercise, early fatigue and delayed recovery.

So, all carbohydrates are converted to glucose and absorbed into blood.  Blood glucose concentrations are maintained between 4-7mmol/l by hormones released from your pancreas called insulin and glucagon.

Insulin reduces glucose in the blood and glucagon releases glycogen from liver and muscles to increase glucose in the blood.

Which carbs should I be eating?

Fruit, vegetables, pulses and wholegrain starchy foods provide a wide range of vitamins and minerals and the fibre in these foods can help to keep your bowels healthy and adds bulk to your meal helping you to feel full. Try to increase the amount of fibre in your diet by choosing wholegrain varieties of starchy foods and eating potatoes with the skins on. Try to aim for an average intake of 30g of fibre a day.

Sweets, chocolates, biscuits, cakes and soft drinks with added sugar are usually high in sugar and calories, but provide very few other nutrients. However, it is completely normal to have these types of foods sometimes, and they taste great!

What happens if we don’t have carbohydrates in our diets?

  • Low carbohydrate diets continue to be popular and get a lot of media attention.  However, they are not healthy, not sustainable, and can put a great deal of extra stress on the body  
  • Muscles are lost as they are used as energy for the body
  • Much greater risk of some cancers – e.g. bowel cancer
  • Tiredness, fatigue, irritability due to low blood sugar levels (no other nutrient provides glucose)
  • Inability to concentrate since the brain primarily uses glucose to work
  • Poor performance – in everyday life and sport

Fat – what should we be eating?

Avocados, oily fish and nuts and olive oil contain healthy fats, one of the macronutrients you need
Avocados, oily fish nuts and olive oil contain healthy fats, one of the macronutrients you need
The body uses different macronutrients for different purposes, so it is important to provide your body with a balance of essential nutrients including fats.

Although fats are often thought of as “bad”, in fact they are completely necessary for our bodies to function.

The reason that there is a lot of media interest in fats and, in particular, emphasis on fat reduction is because a lot of people in the UK are eating a lot more fat than the recommended amounts.

What are fats used for?

  • Providing energy
  • Keeps us warm

    • Dietary fat provides the essential fatty acids linoleic acid and linolenic acid (also known as omega 3 and omega 6 fatty acids). We need to eat these on a daily basis. They are essential for brain function, including the brain development of the growing foetus. They are also very important in improving brain function when returning to a normal weight after being a low weight. They also have a role in preventing heart disease.

  • Absorption of fat soluble vitamins (A, D, E and K) – humans are unable to absorb these essential vitamins without having fats in their diet
  • Palatability of foods – making them taste nice!
  • Providing a protective layer around organs (e.g. kidneys, etc) to protect them from impact, like falls
  • Fats contribute to the structure of blood vessels, and form a major component of cell membranes. A low fat intake will therefore increase the risk of bruising very easily, and affect skin health.
  • Fats transport cholesterol around the body. Many people who are a low weight can have a high cholesterol level, which reduces if fat is added to the diet and weight is gained.
  • Fat contributes to the structure of hormones, such as oestrogen. A lack of oestrogen will lead to a lack of periods, which increases the risk of osteoporosis. Therefore, a diet low in fat may delay the return of menstruation, or the body may need to be a higher weight before periods return if a low fat diet is consumed.
  • Increasing satiety, which means that you will feel fuller more quickly than if you do not include fats. Therefore you will not feel that you have to keep eating/will not be able to stop eating after finishing a meal or snack

Types of fats in our diet

  • Saturated fats: from animal fats and products derived from animal fats (including biscuits, etc). These are necessary to provide cell membrane structure, but can raise LDL blood cholesterol if eaten large quantities
  • Monounsaturated fats: olive, rapeseed and almond oil, nuts, olives, peanut butter
    Most beneficial, especially when used to replace saturated fats

    • Polyunsaturated fats: Omega-3 and Omega-6

Essential Fats

Omega-3 fatty acids are essential for our health and important as part of a balanced diet

Omega-3 fatty acids are essential for our health and important as part of a balanced diet

what are they?

  • They are fats that the body cannot make from other types of fats, so we need to get them from our diet
  • They have important functions in the body, as explained below
  • There are two types: linoleic (n – 6) and alpha linolenic (n – 3). They are also known as omega 6 or omega 3 fatty acids
  • Alpha linoleic acid (Omega 3 fatty acid) is changed in the body to make two other fats, known as EPA and DHA
  • Most people need to eat more omega 3 fatty acids.

    • Omega-3

    Omega-3 is a type of polyunsaturated fat found in fish, fish oils and flaxseeds, among others; omega-6 is found in vegetable oils, vegetable oil based spreads, nuts and seeds (due to them being in vegetable oils they are also found in processed foods, such as biscuits, cakes, crisps, etc). Polyunsaturated fats are essential fats.

    Why are essential fats important?

  • Essential fatty acids are important for keeping cells healthy. A lack of fat and essential fatty acids can cause easy bruising and slow wound healing.
  • DHA is a very important part of the brain, and low levels of DHA have been linked to many emotional and mental health problems, including anorexia nervosa. It may also be relevant for people with bulimia nervosa if they have a very low fat diet, or have been a low weight at any stage prior to developing bulimia.
  • Essential fatty acids may reduce the risk of coronary heart disease and heart attacks by reducing (“bad”) cholesterol levels and increasing HDL (“good”) cholesterol levels.
  • Essential fatty acids may also help to alleviate depression and anxiety and may help to reduce inflammatory conditions, such as arthritis.

    • How much do we need?

    In the UK there are no specific recommendations on how much we should be having. The only guideline is that you should include two portions of fish per week and at least one of these should be an oily fish.

    What if I don’t eat fish, can I have supplements?

    It is best to try and get omega-3 from foods but the following advice may be helpful if you find this difficult and wish to take a supplement:
    • Avoid supplements made from fish liver oil as this has less omega-3 fatty acid and may have more contaminants. Find a supplement made from the oil from the fish body.
    • Check the vitamin A content -The Scientific Advisory Committee on Nutrition (SACN) advises that if you take supplements containing vitamin A, you should not have more than a total of 1.5mg (1500ug) a day from food and supplements combined (also in pregnancy you must not take supplements containing vitamin A)
    • Check labels for DHA and EPA content – stick to the daily amount provided by eating one to two portions of fish per week (about 450mg EPA and DHA per daily adult dose)

    There are currently no UK recommendations for omega-3 supplements as there is not enough evidence that they benefit healthy adults and children.

    Vegetarian sources of omega-3 fats:

    If you are vegetarian then you can get some omega-3 fatty acids from foods:
  • Rapeseed or canola oil (and use an olive oil based margarine)
  • Walnut or soya oil
  • Dark green leafy vegetables
  • Nuts – walnuts, pecans, peanuts and almonds
  • Soya products (like soya beans and tofu)
  • Omega-3 enriched eggs
  • Seeds such as linseed/flax seed (up to 1 dessertspoon a day)
    • Diets that do not contain fat as a macronutrient, not only negatively affect your overall health due to the reasons above, but also tend to be very bulky.

    Fats are not automatically converted into body fat. As long as you are eating the correct amount of energy to maintain your body weight, the fat you eat (and energy you get from the other nutrients) will be used for energy.

    If you need to increase your weight then the energy you consume over and above your needs to maintain your weight, will be used to start to replenish your muscles. You will also notice that your fat stores do increase (adipose tissue) and this is entirely necessary for recovery to full health.

    Protein: Your Body’s Building Blocks

    What is protein?

    Protein is a macronutrient that is found throughout the body—in muscle, bone, skin, hair, and virtually every other tissue.

    Protein is required by the body for many different functions including:

    • Growth and repair of body tissues
    • transporting nutrients around the body
    • forming enzymes
    • antibodies

    Foods high in protein:

    You can think of proteins as intricate puzzles, made up of more than 20 amino acids—some are essential amino acids (meaning you need them from your diet) and some are non-essential (ones that your body can make from others you get from the diet).

    Amino acids are found in animal products (as complete protein) and a few plant sources (as incomplete protein).

    Plant-based proteins

    Incomplete proteins usually don’t have all nine essential amino acids so if most of your protein comes from plants, make sure that you eat a wide variety of different sources of plant-based proteins on a daily basis.
    – Good sources of plant-based protein include: tofu, chickpeas, lentil, baked beans, nuts, and kidney beans.

    Animal-based proteins

    Red meats, poultry (chicken, turkey, duck), a variety of seafood (fish, crustaceans, mollusks), eggs and dairy products are your best bet.
    These protein rich foods also provide iron, calcium, vitamin B12 and omega-3 too.
    Fish, beans and nuts contain the macronutrient protein

    Fish, beans and nuts contain the macronutrient protein

    What happens when we don’t consume enough protein?

  • Loss of muscle mass
  • Hair loss and brittle nails
  • Poor wound healing and increased risk of infection
    • We know that most people in a western society do meet their protein needs, as long as they are meeting their total energy needs and are at a healthy bodyweight (i.e. not underweight).

    How much protein should I eat?

    Protein should contribute to 15% of our total energy.
    Current guidelines suggest we should be consuming 0.75g of protein per kg of body weight – on average this is around 56g protein for men and 45g protein for women.

    45g could look like:
    3 medium eggs, 1 fillet of salmon and a handful of nuts

    Although protein is an essential part of our diet – it is equally important to have enough carbohydrate and fat in our diets to maintain energy levels throughout the day, reduce feelings of fatigue and stop muscles being broken down for energy.

    Very high protein diets that cut out or drastically reduce other macronutrients are not helpful for anyone and this can lead to eating disorder development.

    Conclusion

    Understanding the macronutrients, carbs, fats and protein, is key to a healthier, happier you. So, embrace the knowledge, make informed choices, and let these nutritional heroes guide you on your journey to wellness. As boring as it may be, balance is really the key.

    Remember, we’re here to support you every step of the way! Contact us to find out more info@jlnutritionclinic.com.

    Jen Owner of JL Nutrition Clinic