The Ultimate Guide to Protein

An evidence based guide to everything you ever needed to know about protein for health, sports performance and weight loss.
An evidence based guide to everything you ever needed to know about protein for health, sports performance and weight loss.

Protein has become the buzzword for selling nearly every food product from yoghurts to chocolate brownies. Over the past decade or so there has been a noticeable increase in protein supplements and “high” protein food products. With proteins rapid rise in popularity, it’s hard to figure whether protein is a exemplary food group or just hype. Is protein actually beneficial for health and fitness or is it just another way to market us new products?

If you are looking for clarity on protein for health, sports performance and weight loss than this article is for you. This guide to protein discusses the most common questions with explanations that are back by science so that you can make informed decision about your diet.

What is protein and why is it necessary?

Protein is one of the three macronutrient we need in our diets in large amounts, alongside carbohydrates and dietary fats. Each gram of protein contains 4 calories. Chemically, proteins are a made up of amino acids joined together in long chains. There are 20 different amino acids which make up all the proteins in your body. Some amino acids are considered non-essential as your body produces them on its own. However other amino acids are essential because we can only get them food.

Protein is in every cell of your body, it used to create tissues such as muscle, skin and hair. In fact, hair and nails are made up of mostly exclusively of protein. Protein is also used to make enzymes, hormones, and biochemical reactions.

Proteins are constantly being broken down and replaced in the body. Usually the amount broken down is in line with the amount being made by the body however your body might need more protein if you’re recovering from injury/illness, pregnant, breastfeeding or very active. Unlike the other macronutrients, protein is not stored by our body as excess protein is converted to energy or fat. Therefore, we need to eat protein regularly on a daily basis.

What are the benefits of eating a diet high in protein?

Speeding up recovery after exercise

Intense exercise causes damage to the muscle fibre which is then repaired after your workout. When the fibres are rebuilt they better adapted to tolerate future stress (the exercises practiced) because they are now reformed bigger and stronger. Eating protein pre-/post-workout increases muscle protein synthesis, a process where muscle damage from intense exercise is repaired by protein produced, when combined with sufficient daily total caloric and protein intake.

Reducing muscle loss

Most of us diet or reduce calories with the aim to lose weight but more specifically lose body fat. However, when we reduce our calorie intake and/or increase our calorie expenditure through exercise we can unintentionally lose muscle as well. This happens because the bodies first energy source is glucose or carb but when we are dieting there is less glucose available and therefore our bodies will use glycogen for energy instead which is stored in the liver and muscles.

Metabolism slows because muscle burns more calories than fat, making it harder maintain your weight or lose body fat. A high protein diet prevents muscle loss during weight loss by increasing the intake of protein when there is a higher demand for it

Building lean muscle

Increased lean muscle mass is not just aesthetically appealing, it also increases your metabolism and your physical fitness levels. High protein intake helps create an anabolic state, increasing lean body mass when combined with progressive resistance training, balanced diet and sufficient recovery.

Curbing hunger

Protein is more satiating than carbohydrate or fat. Several studies have found that higher protein intakes promote more satiety and reduce hunger. One study found that high protein snacks allowed people to longer between eating and caused them to eat less in the following meals.

Protein digestion increases energy expenditure

Protein increases the thermic effect of food, which is the amount energy used to digest a meal and turn it into energy. Although the effect is quite small, increasing energy expenditure by around 6-8kcal per hour, it is a nice little bonus of eating more protein.

How much protein do I need?

In the UK, The Department of Health reference protein intakes based on an average-sized woman doing an average amount of physical activity is only 45g of protein or 180kcal worth of protein. With similar guidance in the US. Unfortunately, I feel this guidance is very one-size-fit-all, vague and outdated. Furthermore, governmental dietary guidelines are often set at the minimum amount needed to avoid malnutrition versus the optimal amounts required to thrive.

A significant amount of scientific research supports higher protein intakes. Also, how much protein you need depends on a number of factors, such as;

  • weight
  • body composition
  • goals – for example do you want maintain weight, lose body fat or gain muscle
  • lifestyle factors – how sedentary or active you are on a day-to-day basis
  • if you do physical exercise – and more specifically the type, intensity, duration and frequency of exercise
  • whether you are pregnant or breastfeeding

Protein for physically active individuals

A review of research on the protein needs of individuals who are physically active found that protein intake of 1.2-2.2 grams per kilogram of bodyweight was sufficient for those who are either maintaining their weight or trying to gain muscle.

Grams of Protein = Bodyweight in kg* x 1.2 – 2.2

However, the demand for protein is higher for individuals restricting their calories for fat loss. Therefore, protein intakes of 1.8-2.7 grams per kilogram of bodyweight is optimal.

Grams of Protein = Bodyweight in kg* x 1.8 – 2.7

Protein for sedentary individuals

Research suggest that protein intakes for healthy individuals who do little or no physical activity should be around 1.2-1.8 grams per kilogram of bodyweight. However, body composition change is most effective when couple with physical exercise.

Grams of Protein = Bodyweight in kg* x 1.2 – 1.8

Protein for obese individuals

There is a slight caveat for anyone who is very overweight or obese as the following the previous recommendation would give you a very high protein intake. Guidance of 1.2-1.5g per kilogram of bodyweight is suggested however it may be beneficial to calculate your protein based on fat-free mass or your ideal bodyweight.

Grams of Protein = Bodyweight in kg* x 1.2 – 1.5

Which foods are high in protein?

Meat sources

  • Lean Chicken Breast
  • Turkey Breast
  • Lean Pork Chops
  • Lean Beef
  • Jerky

Fish & Seafood

  • Tuna
  • Oily fish; Salmon, sardines and mackerel
  • White fish; cod, haddock, pollock, flounder, halibut, tilapia
  • Prawns
  • Mussels


  • Eggs and Egg Whites
  • Cottage Cheese
  • Greek Yoghurt, Icelandic Yoghurt
  • Quark
  • Milk
  • Cheese; parmesan, cheddar, mozzarella

Plant based sources

  • Nuts; almonds, pistachios, cashews
  • Nut butters and powdered peanut butter
  • Pulses; black beans, butter beans, chickpeas, lentils
  • Edamame, soy, tofu and tempeh
  • Seeds; hemp, chia, pumpkin seeds
  • Grains; spelt, quinoa, bulgur wheat
  • Meat substitutes; Quorn, Impossible Burger

Can you get enough protein from a plant-based (vegan or vegetarian) diet?

Healthy diet vegan food, veggie protein sources: Tofu, vegan milk, beans, lentils, nuts, soy milk, spinach and seeds. Top view on white table.

Yes, you can.  Diversity is key here however; if you’re eating a varied diet containing different pulses, grains, nuts and seeds you should be able to get a sufficient amount of protein and essential amino acids.

When should I eat protein (nutrient timing)?

Nutrient timing refers to strategically eating foods at specific times to optimise either performance, muscle gain or fat loss. Research in the past has put an emphasis on eating carbs and protein post-workout within the anabolic window, thought to be 30-60 minutes after you finish your workout. However more recent findings have shown that total daily protein and carb intakes are more important than nutrient timing for the average individual.

I like to have a portion of protein with each meal and snack on protein in between meals. On workout days I like to have a protein shake or Greek yoghurt an hour before I exercise then a meal including protein about an hour afterwards. This is what works for me as protein evenly spaced throughout day keeps my appetite in check.

When it comes to protein, meal and snack timing, do you – what you eat and how much you eat is far more important than when you eat.

Should I use a protein powder?

Protein supplements and products have become increasingly popular. It seems like every gym bunny and health enthusiast is guzzling down a protein shake or chomping on a protein bar – but are protein supplements just hype or a necessity?

Protein powders are essentially a quick and easy way to get more protein in your diet. Per kilo they are usually a lot cheaper than other sources of protein. They are also really convenient as they are quick to prepare (usually just mixed together with water, cow’s milk or milk alternative) and highly portable. There are numerous types of protein powder, but a typical protein powder will be fairly low calorie and boast around 15-30g of protein per scoop.

It is possible to get all of the protein you need without using supplement therefore rotein supplement are definitely not essential, but with being said they can be useful diet aid.

They are quite a few types of protein powders:

Dairy Protein Powders

  • Whey Protein is derived from milk. It’s a complete protein as it contains all 9 essential amino acids. It digests quickly and usually has a relatively low lactose content. It’s generally used pre and post workout.
  • Casein Protein like Whey comes from milk and is a complete protein. However, unlike Whey, casein digest much slower. Casein is commonly used before going to sleep or before periods of fasting.
  • Egg Protein is made from egg whites. It’s a complete protein. There’s not as much research on Egg protein however it’s a good choice for those with milk allergy.

Vegan & Vegetarian Proteins

  • Soy Protein is made from soybeans. Despite it being plant based, it is a complete protein. It’s somewhat controversial ingredient as the majority of soy is genetically modified and it also has been linked to health issues.
  • Pea Protein is a popular option for vegans and vegetarian. It’s a complete protein containing all the essential amino acids.
  • Brown Rice Protein is another plants-based option. It has lower levels the amino acid lysine, therefore it’s not a complete protein.

What are BCAAs?

BCAAs or Branched-Chain Amino Acids are group of three essential amino acids; leucine, isoleucine and valine. Branched-Chain refers to the chemical structure of the amino acids. BCAA supplements are used support muscle maintenance, growth and recovery.

However, BCAA supplements are an incomplete protein as they only contain three of the nine essential amino acids. Additionally, BCAAs can be found in complete protein sources such as whole protein supplements (like Whey or Pea Protein) or high protein foods.

Can you have too much protein?

High protein intakes have been shown to increase kidney damage in individuals who already have kidney although there is no link to kidney damage for healthy individuals.

It was previously thought high protein intakes could cause osteoporosis however studies show in the long-term high protein intake contribute to better bone health.

For the most part relatively, high protein is healthy however if you eat more calories than your body needs of any macronutrient this will lead to weight gain.

Nayomi Pennant
I’m an utter foodie who is passionate about wellbeing, health & fitness. I created Her Food and Fitness to share delicious nutritious recipes & feasible fun fitness advice for women. My mission is to provide women with food and fitness advice on how to lose fat, build lean muscle and stay healthy.