What are protein, carbs and fats?

By Juliana Kassianos, Transformational Fertility Coach, Yoga Teacher and Founder of The School of Fertility



  • Protein, Carbohydrate and Fats

  • Nutrients required in large amounts


  • Provide energy to the body

  • Enable the body to function properly


Proteins aren’t used as they are found in food, but are broken down into amino acids. These amino acids are vital for manufacturing reproductive hormones, such as luteinising hormone and follicle stimulating hormone, as well as for heathy egg and sperm production. Therefore, it’s important to have a diet high in protein when trying to conceive.

There are 20 different amino acids and eight of them are essential. This means they have to be supplied through the food you eat.

Whereas animal proteins like meat, eggs, dairy products, fish and poultry, otherwise known as ‘complete proteins’, contain all eight amino acids, many non-animal protein sources such as vegetables, beans, legumes, nuts and seeds are ‘incomplete proteins’, as they don’t.

You may not eat animal protein because of health concerns or environmental and ethical factors, in which case plant proteins are a good alternative. Beans, legumes and whole grains are the richest vegetable sources of protein, but can lack in one or two essential amino acids. But those lacking in beans and legumes are normally supplied in wholegrains. Therefore, combining all of them in your diet can ensure you get all the essential amino acids your body needs.

One study showed that replacing animal sources of protein, including chicken and red meat, with vegetable sources of protein, may reduce the risk of infertility due to anovulation (lack of ovulation).

Should I eat red meat?

Be aware that red meat can trigger inflammation in the body and has been linked with increased risk of endometriosis. However, it is a good source of L-arginine; an amino acid. According to one study, oral supplementation of the amino acid L-arginine in those who respond poorly to IVF, may improve ovarian response, endometrial receptivity and pregnancy rate. Non-meat food sources include spirulina, pumpkin seeds and chickpeas. For men L-arginine has shown to improve sperm motility. Make sure any red meat consumed is lean, unprocessed and is grass-fed.

Red meat is also a source of L-carnitine and L-acetyl-carnitine for men. One study showed administration of L-carnitine and L-acetyl-carnitine to sperm samples lead to improved sperm quality and chromatin quality. Non-red meat food sources include chicken and avocado.

What fish can I eat?

When eating fish, stick to the following which are high in healthy omega-3 fatty acids: Salmon, Mackerel (not King Mackerel), Anchovies, Sardines and Herring. Make sure they’re wild caught, as farmed fish may contain residues of antibiotics. Avoid eating the following deep-sea dwelling sh as they tend to contain high concentrations of mercury; a toxic heavy metal linked to infertility.

  • Blue fin Tuna

  • Canned Albacore

  • Tuna

  • Yellow fin Tuna

  • Atlantic Halibut

  • Sea Bass (from Crozet, Prince Edward, Marion Islands, Chile)

  • Grouper

  • Monk fish

  • Orange Roughy

  • Farm Raised Salmon (wild caught is fine)

  • Sword fish

  • Shark

  • Tile fish

  • King Mackerel

  • Marlin


Carbohydrates are divided into two types: simple and complex. Simple carbohydrates such as sucrose (table sugar), fructose (fruit sugar) and lactose (milk sugar) are digested and absorbed quickly, providing you with a burst of energy, normally followed by a slump.

Complex carbohydrates found in wholegrains, vegetables, beans and legumes and fruit, are digested and absorbed much more slowly, providing you with a steady stream of energy, keeping your batteries running throughout the day. These are the type you want to make sure you have in your diet.

Fibre is a complex carbohydrate found in plant foods like wholegrains, vegetables and fruit. It can’t be digested by the body, so it doesn’t provide us with energy. This is because the body doesn’t have enzymes that are able to break it down. However, fibre has many health benefits, including helping the body to get rid of excess oestrogen and controlling blood sugar levels, as it slows the absorption of sugar.

If you think you need to increase your daily intake of fibre, make sure you do it slowly. If you do it too fast, you might find yourself feeling bloated and producing a lot of gas. Also, make sure you drink lots of water.

Soluble fibre found in oat bran absorbs water, which slows down the rate that food leaves your stomach, so this helps you to feel full. Insoluble fibre found in wheat bran retains and traps water, this helps soften your stools and prevent constipation. So, you need to keep hydrated.

Some of the signs that you might not be getting enough carbohydrates in your diet are if you feel like your batteries are running low, suffer from headaches and have dizzy spells.


Fats in particular are a high-density energy source as they provide more than double the number of calories per gram compared to proteins and carbohydrates; nine versus four. If you consider calories to be the archenemy, don’t start thinking you should completely cut fats out of your diet as they provide the necessary precursors for healthy hormone levels needed for optimal fertility.

There are four types of fats: trans fats, saturated fats, monounsaturated fats, and polyunsaturated fats. Not all fats are the same; some are healthier than others. The trick is to learn to separate the ‘good’ from the ‘bad’ and mindfully moderate intake.

Trans Fats

Trans fats are the ultimate ‘baddies’ being the lowest in quality. They’re produced artificially in a process known as hydrogenation, where hydrogen is added to liquid vegetable oil turning it into solid fat. The food industry loves them as they increase the shelf-life of produce, but unfortunately so do we... They give taste and texture to processed, fried and baked foods like margarine, frozen pizza and doughnuts.

In the last few years, a lot of food manufactures have removed trans fats from their products, but we still need to watch out for them. Unlike in America, there are currently no legal requirements for manufactures in the UK to label trans fats. This means the best you can do is to check ingredient lists for hydrogenated and partially hydrogenated vegetable oils and try to avoid them.

Saturated Fats

Saturated fats are found in butter, cheese and biscuits and are ones to avoid. There is one exception to the rule though and that’s coconut oil. Most vegetable and seed oils contain long-chain fatty acids that are difficult for our body to break down, put a strain on our digestive system and are mainly stored in our body as fat. However, coconut oil contains medium-chain fatty acids, which are smaller, easier for our body to digest and are sent directly to our liver, where they are converted into energy rather than being stored as fat.

Monounsaturated Fats

Monounsaturated fats are ‘good’ fats found in avocado, oils such as olive oil, as well as some nuts like almonds. These are the healthy fats we want to make sure we’re getting in our diet.

Polyunsaturated Fats

Polyunsaturated fats include Omega-3 found in oils such as linseed and oily fish, and Omega-6 found in nuts and seeds. They’re both ‘essential’, which means we need to get them from the food we eat or in supplement form as our body can’t make them. Whilst Omega-3 is anti-inflammatory, Omega-6 is pro-inflammatory. For this reason, we need to make sure we try to have a balance of the two in our diet.

Omega-3 has been shown to enhance sperm count, motility, and morphology. Good sources include oily fish such as Salmon, Mackerel (not King Mackerel), Anchovies, Sardines and Herring.

Researchers believe walnuts, comprised of predominantly polyunsaturated fatty acids reduce peroxidation; a process that damages sperm cells.

Why choose full-fat

A lot of us have a full-fat phobia, after all, why pile on those extra calories when we can go for a fat-free or low-fat option instead? However, this is a mind-set we should challenge.

Fats are the main nutrient in our body that make us feel full. Just like oil floats on water, fats float on the surface of the foody/liquid mixture in your stomach. This limits the effect of fat-busting digestive enzymes, which means the fats are digested slower than the proteins and carbohydrates. This is the reason after a high-in-fat meal you’re left feeling full.

So, if we eat fat-free food, we can end up wanting more as our bodies don’t feel satisfied. This is coupled with the fact that sometimes we think because we’re eating fat-free foods we’re being ‘good’ and so help ourselves to another serving. However, this can result in us eating a larger portion than if we’d just eaten the full-fat version in the first place. What’s more, the food industry often replaces fats with stack loads of sugar to mask the flavour.

Next time you’re in the supermarket, think twice before buying fat-free and low-fat foods. Ask yourself the following: Will the alternatives satisfy you? Are you including any other source of fats in your diet? Is sugar replacing the fats in the alternative? Will you end up eating a larger portion than you would if you’d just had the full-fat version?

Take note that one study showed consuming high-fat dairy foods may decrease the risk of anovulatory infertility (lack of ovulation). Although dairy products can trigger inflammation in the body, full-fat yoghurt is a good option, as it supports a healthy balanced gut bacterium necessary for lowering inflammation, processing toxins and reducing toxin exposure to a developing foetus.


  • Protein intake and ovulatory infertility. Jorge E. Chavarro et al. Am J Obstet Gynecol. 2008 Feb; 198(2): 210.e1–210.e7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3066040/

  • L-arginine and male infertility. Scibona M et al. Minerva Urol Nefrol. 1994 Dec;46(4):251-3. https://www. ncbi.nlm.nih.gov/pubmed/7701414

  • Adjuvant L-arginine treatment for in-vitro fertilization in poor responder patients. Battaglia C et al. Hum Reprod. 1999 Jul;14(7):1690-7. https://www.ncbi.nlm.nih.gov/pubmed/10402369

  • Effects of L-carnitine and L-acetyl-carnitine on testicular sperm motility and chromatin quality. Elham Aliabadi et al. Iran J Reprod Med. 2012 Mar; 10(2): 77–82. https://www.ncbi.nlm.nih.gov/pmc/articles/ PMC4163266/

  • The roles of omega-3 and omega-6 fatty acids in idiopathic male infertility. Safarinejad M.R and Safarinejad S. Asian J Androl. 2012 Jul; 14(4): 514–515 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3720081/

  • Effectiveness of a walnut-enriched diet on murine sperm: involvement of reduced peroxidative damage. Coffua L. S and Martin-DeLeon P.A. Heliyon. 2017 Feb; 3(2): e00250. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5318272/

  • A prospective study of dairy foods intake and anovulatory infertility. Chavarro JE et al. Hum Reprod. 2007 May;22(5):1340-7. Epub 2007 Feb 28. https://www.ncbi.nlm.nih.gov/pubmed/17329264

  • In part adapted from an article written for Breathe magazine (Issue 6) by Juliana Kassianos

Juliana Kassianos