Fats, Carbs, Protein, Fibre & Salt – What do we need?

Fat, carbohydrate, protein and fibre are known as ‘macronutrients’ because we need them in large amounts in our diets. These nutrients are responsible for providing us with energy as well as having a number of other specific functions. You’ll see these labelled on most food items. Although salt is a mineral, we consume it in relatively large amounts so it’s listed in the nutritional information on food labels along with the macronutrients.

Fat

We need fat in our diet. The reason that fats get such a bad rap is that many of us consume too much of the wrong types of fat. Fat is required for growth, development and cell function^[1]. There are two fatty acids which are essential and we need them to survive; these are linoleic acid (LA – an omega-6 fatty acid) and alpha-linolenic acid (ALNA – an omega-3). In addition, there are four semi-essential fatty acids that themselves have health benefits, and they can reduce the requirement for LA and ALNA^[2]. These are arachidonic acid (AA), gamma-linolenic acid (GLNA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). If you do not include sufficient of these four in your diet, then you need to make sure you’re including plenty of foods that contain LA and ALNA.

There are different types of fat:

Saturated fats - these have historically been associated with an increased risk of developing cardiovascular disease (CVD) when consumed in excess as too much can increase your total cholesterol level. However, more recent evidence has indicated that saturated fats may not be the main culprit for CVD but it would still be wise to not over-consume them^[3].

Monounsaturated fats - monounsaturated fats may help to lower the level of 'bad', i.e. LDL, cholesterol in our blood while keeping 'good', i.e. HDL, cholesterol high^[4]. Olive and rapeseed oils are rich in monounsaturates, and these fats are also found in small amounts in many nuts and seeds and their oils.

Polyunsaturated fats - there are two main sub-grounds of polyunsaturates: omega-3s found in the seeds and oils of flaxseed (linseed), rapeseed and walnuts as well as oily fish, and omega-6s derived from other seed oils, such as sunflower and soya oil. Both types of fatty acids are essential to humans, as they cannot be made in the body from other nutrients.

The balance of how much omega-3s and 6s is important for health. Most of us are consuming too many omega-6s and not enough omega-3s; ideally, we should aim to consume them in a ratio of at least 1:1-2 (omega 3:6)^{[5, 6]}.

EPA and DHA are the omega-3s that are predominantly found in oily fish, fish oils and the algae eaten by the fish. If you don’t consume oily fish, then you need to ensure you’re having a good intake of plant sources of omega-3s^[7]. You can read more about this here.

One principal reason why there is overconsumption of omega-6s is that many processed and junk foods are made from these oils which are tasty and cheap to use so they are added in large amounts. These oils are heavily processed and therefore the fats can become oxidised – or rancid during processing^[8]. These, in turn, are atherogenic or plaque-forming – the initial process involved in the pathology of CVD^[9]. We need to include some omega-6s in our diet, but make sure they’re from plant sources where the oil hasn’t been subject to oxidation.

trans fats - trans fatty acids are predominantly industrially produced during the creation of 'hydrogenated' fats, and they are used in margarines and manufactured foods like cakes, pies and biscuits. They confer texture and shelf-life benefits on manufactured foods. These are atherogenic and should be avoided as much as possible^[10].

MCTs - medium-chain triglycerides (MCTs) are types of fat that are absorbed and metabolised more like carbohydrates than fats^[11]. Structurally speaking they are saturated fats, but they are processed in the body in a different way, and they provide a very energy-dense, efficient source of fuel. A great source of MCTs is coconut oil.

Key points

• Not all fat is bad; you need to include a good amount each day
• Oils rich in monounsaturates can be useful to include
• Consume foods rich in omega-3 fatty acids
• Include omega-6 fats from good-quality plant foods
• Avoid trans fats and partially hydrogenated oils
• MCT fats can be useful
• All Huel products have the right balance of omega-3s : omega-6s and is rich in monounsaturates and MCTs

Read more about fats in our article Good Fats & Bad Fats.

Carbohydrate

Whilst not essential per se, carbohydrates are extremely useful as an efficient source of energy.

There are two groups of carbs: mono- or disaccharides, aka ‘simple’ carbs, and polysaccharides or ‘complex’ carbs, e.g. starch. Simple carbs include sugars, which are fast acting; in other words, they are digested and absorbed rapidly, consequently causing a sharp rise and fall in blood glucose.

Many complex carbs are digested more slowly, but there are some that are still broken down quite quickly. Complex carbs include rice, oats, potatoes, couscous, quinoa, other cereals, etc. The Glycaemic Index (GI) is a guide to how slowly carbohydrate containing foods are digested and absorbed. High GI foods are digested and absorbed more quickly which has a more pronounced effect on blood glucose than low GI foods.

Try to consume more complex carbohydrates from wholefoods as these foods tend to be higher in fibre and vitamins and minerals than processed foods. They’re also more filling^[12].

Key points

• Minimise intake of sugary foods
• Include low GI, complex carbs as the basis of each meal
• All Huel products have a low GI below 30 and digestible carbohydrates provide around 35% of the total calories

Fibre

Fibre is actually carbohydrate; it’s all the polysaccharides that humans can’t digest. There are two main groups: insoluble and soluble. Cereals, seeds and vegetables are rich in insoluble fibres – these are great for a healthy digestive system and help fill you up and stop you snacking.

Soluble fibre is found in pulses (peas, beans and lentils), oats and fruit. Not only do these help maintain a healthy digestive system, but they also can help reduce the risk of CVD^[13]. Oats are rich in a particularly effective soluble fibre called beta-glucan^[14].

We should all be including plenty of fibre at each meal, and many fibrous foods are also rich in vitamins and minerals. In addition, it’s vital to consume plenty of water to get the most out of your high fibre intake as fibre acts like a sponge.

Key points

• Fibre helps maintain a healthy gut and also helps fill you up
• Eat high-fibre foods at each meal
• Include plenty of cholesterol-lowering soluble fibre foods each day. Oats are particularly good
• Huel products are rich in insoluble and soluble fibres

Protein

Protein is essential for the structure of many tissues including muscle, skin and tendons, as well as being a constituent of substances involved in biological processes in the body like enzymes, hormones and antibodies to fight infection.

There are 20 principle amino acids in nature and humans need to include 9 of them in our diet. The 9 essential amino acids are:

• Histidine
• Isoleucine
• Leucine
• Lysine
• Methionine
• Phenylalanine
• Threonine
• Tryptophan
• Valine

All these amino acids have to be included in significant amounts each day. However, one amino acid that needs a particular mention is leucine. This is because it is the amino acid that ‘switches on’ protein synthesis^{[15, 16]}. An enzyme called mTor is the key enzyme that initiates protein synthesis in tissues, and when the level of leucine reaches a certain amount, mTor is switched on and protein synthesis commences. If there’s too little leucine present, then protein synthesis is not ‘switched on’. The amount of leucine that we need to consume in order to keep protein synthesis seems to be over 2.5g per meal three times per day^{[17, 18]} and must be in combination with other amino acids^[19].

Although it’s hard in the Western diet to have an insufficient amount of daily protein, it’s not uncommon for each meal to be too low in protein. Since most proteins are between 5% and 10% leucine^[20], this means that protein synthesis will not be triggered to its fullest degree and not all the protein will be used for anabolic functions. Instead, it will be used for energy and, if there’s sufficient energy, it will be stored as body fat.

Read more in our article Guide to Protein Quality, Digestion and Absorption.

Key points

• Consume high-protein foods each day
• If you partake in regular exercise, then you may need to consume more protein foods
• All Huel Products are high in protein
• The core Huel Powder contains over 2.53g of leucine per 400kcal and Huel Black Edition contains 3.45g. Huel Ready-to-drink contains over 1.6g of leucine per bottle and per Huel bar there’s over 1.7g.

Salt

Salt is sodium chloride. Both sodium and chloride are essential electrolytes that we need to consume every day. The problem is most of us consume too much salt as it's added as a preservative and flavour enhancer to many snack and convenience foods^[21]. Sodium is found naturally in many foods, and around 90% of the sodium most people consume is in the form of salt.

Salt can be beneficial for helping hydration, which is why isotonic drinks contain sodium and other electrolytes. If you’re an active person, then include at least 2.5g salt per day, but no more than 6g per day.

Key points

• We need some salt in our diet but most of us consume too much with modern diets
• All Huel Products contain a relatively low amount of salt to ensure people get enough but do not over consume

More information

• The Beginner's Guide to Nutrition
• Huel: The Formula Explained
• The 26 Essential Vitamins and Minerals - Deficiencies and Toxicity

References

1. EUFIC. The Functions of Fats in the Body. Date Accessed: 04/09/19. [Available from: https://www.eufic.org/en/whats-in-food/article/facts-on-fats-dietary-fats-and-health]
2. Hamosh M. Overview: Conditionally Essential Nutrients: Can Long-Chain Polyunsaturated Fatty Acids and Nucleotides Qualify? In: Newburg DS, editor. Bioactive Components of Human Milk. Boston, MA: Springer US; 2001. p. 357-63.
3. Forouhi NG, et al. Dietary fat and cardiometabolic health: evidence, controversies, and consensus for guidance. BMJ. 2018; 361:k2139.
4. Kris-Etherton PM, et al. High-monounsaturated fatty acid diets lower both plasma cholesterol and triacylglycerol concentrations. The American journal of clinical nutrition. 1999; 70(6):1009-15.
5. Simopoulos AP. The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomed Pharmacother. 2002; 56(8):365-79.
6. Russo GL. Dietary n-6 and n-3 polyunsaturated fatty acids: from biochemistry to clinical implications in cardiovascular prevention. Biochem Pharmacol. 2009; 77(6):937-46.
7. Stoll AL. The Omega-3 Connection: Simon & Schuster; 2001.
8. German JB. Food Processing and Lipid Oxidation. In: Jackson LS, et al., editors. Impact of Processing on Food Safety. Boston, MA: Springer US; 1999. p. 23-50.
9. Staprans I, et al. The role of dietary oxidized cholesterol and oxidized fatty acids in the development of atherosclerosis. Mol Nutr Food Res. 2005; 49(11):1075-82.
10. Dhaka V, et al. Trans fats-sources, health risks and alternative approach - A review. J Food Sci Technol. 2011; 48(5):534-41.
11. Dean W and English J. nutritionreview.org. Medium Chain Trigylcerides (MCTs). Date Accessed: 28/10/19. [Available from: https://nutritionreview.org/2013/04/medium-chain-triglycerides-mcts/]
12. Holt SH, et al. A satiety index of common foods. Eur J Clin Nutr. 1995; 49(9):675-90.
13. Threapleton DE, et al. Dietary fibre intake and risk of cardiovascular disease: systematic review and meta-analysis. BMJ : British Medical Journal. 2013; 347:f6879.
14. Ho HV, et al. The effect of oat beta-glucan on LDL-cholesterol, non-HDL-cholesterol and apoB for CVD risk reduction: a systematic review and meta-analysis of randomised-controlled trials. Br J Nutr. 2016; 116(8):1369-82.
15. Norton LE, et al. Leucine regulates translation initiation of protein synthesis in skeletal muscle after exercise. J Nutr. 2006; 136(2):533S-7S.
16. Breen L, et al. Leucine: a nutrient 'trigger' for muscle anabolism, but what more? J Physiol. 2012; 590(9):2065-6.
17. Paza Dl S, et al. Leucine: Considerations about the Effects of Supplementation. 2015.
18. Koopman R, et al. Combined ingestion of protein and free leucine with carbohydrate increases postexercise muscle protein synthesis in vivo in male subjects. Am J Physiol Endocrinol Metab. 2005; 288(4):E645-53.
19. Stock MS, et al. The effects of adding leucine to pre and postexercise carbohydrate beverages on acute muscle recovery from resistance training. J Strength Cond Res. 2010; 24(8):2211-19.
20. Mero A. Leucine supplementation and intensive training. Sports Med. 1999; 27(6):347-58.
21. Cordain L, et al. Origins and evolution of the Western diet: health implications for the 21st century. The American journal of clinical nutrition. 2005; 81(2):341-54.