How much protein do I need?
Whether you’re trying to bulk up, lose weight or just maintain muscle mass, getting your protein intake right is critical. How much is right for you will depend on a number of factors including your individual health and training goals. How much protein you need has been a topic of much discussion with issues often raised over the safety of high protein diets. This article will look to clear things up where protein is concerned and outline how much you need to help you achieve your goals.
What is protein?
Protein is essentially a macronutrient made up of amino acids. Specifically, 9 essential amino acids and 11 non-essential amino acids. Essential aminos are the most important for their effect on your body’s muscle protein synthesis – the process in which your body builds muscle and you can only get essential amino acids in the diet as the body cannot produce them. Not all protein sources are the same with some containing more essential amino acids than others.
Proteins are used all over the body and not just for muscle. Your body is made up of 100s of different proteins and each one plays a key role in a number of cell functions. Regardless of your body composition or fitness goals, it’s essential you consume enough protein for health reasons.
How much protein do you need each day?
Due to the wide range of actions that proteins are responsible for, the RDA for protein is 0.8g/kg/d, which is the minimum you should look to get in. The optimal intake depends on your body composition, training goals and other calorie and macronutrient requirements.
In athletic individuals training for a certain goal, optimal intakes can range from 1.2 – 2.5g/kg/d.1 For those dieting and aiming to lose weight, protein intakes may need to be on the upper end of that range as evidence shows keeping protein intake during an energy deficit will help preserve your lean muscle mass.
Protein for weight loss
In order to lose weight, you need to be in a calorie deficit. A substantial calorie deficit will increase the likelihood of losing muscle mass as well as fat mass.2 Muscle mass plays a critical role in keeping us healthy as it is important for strength, movement, injury prevention and metabolic control.
Maintaining lean muscle mass will also help to prevent any weight regain after following a diet.
In a study comparing a protein intake of 2.4g/kg/d to 1.2g/kg/d whilst completing resistance exercise whilst in a substantial energy deficit, those with an intake of 2.4g/kg/d preserved more muscle mass.2 Whilst you may not need to go as high as 2.4g/kg/d, in order to maintain muscle mass in an energy deficit, the recommended protein intake is between 1.4-2.4g/kg/d.
Another key reason for getting your protein intake right whilst for a weight loss plan is protein’s effect on satiety.5 Protein will help keep you fuller for longer which may mean you do not snack as often and take on more overall calories than you need.
Protein for muscle and strength
For building muscle, the optimal protein intake is 1.6g/kg/d.1 Building both muscle and strength is an energy dependent process and you will require an appropriate number of calories from other macronutrients in order to hit your overall energy requirements. Whilst it may be possible to build muscle in an energy deficit, the textbook guidelines recommend an energy surplus of 250-450 kcals to increase muscle mass.
Due to the protein's effect on satiety (feeling of fullness) after a meal, it may be difficult to meet high energy demands with protein intakes above 1.6g/kg/d. Additionally, for optimal recovery and performance, calories may be better spent on carbohydrates as full glycogen levels will help you perform at your best during high intensity resistance training sessions.
For strength/power athletes the recommended intake is 1.6-1.8g/kg.1 For those competing in weight categorised strength sports (weightlifting and powerlifting etc.), a slightly higher intake of 2g/kg/d may even suit you better as a high protein intake will limit excess calories to its effect on satiety. 2g/kg/d may allow you to train and recover properly whilst simultaneously preventing unwanted weight gain due to any excess calories.
Do vegans need more protein?
Animal protein sources have more essential amino acids than plant sources.6 Essential amino acids are the key element when assessing a protein’s source ability to increase muscle protein synthesis rates. Specifically, there is a branched-chain amino acid called leucine which acts as a ‘trigger’ to increase muscle protein synthesis.
In order to have the same impact on increasing muscle protein synthesis, vegans may need more of a protein source to get enough essential amino acids. However, there is evidence to show that supplementing leucine when consuming a vegan protein source with less essential amino acids will to ‘rescue’ that protein source and allow it to have the same impact on increasing muscle protein synthesis.
Do women need less protein than men?
Regardless of whether you are male or female, protein requirements are the same, as protein is utilised in the same way. However, using a g/kg measurement will mean you need less absolute protein on a daily basis – so females may not need to eat as much protein or fish to hit their protein requirements as males. An intake of 0.3g/kg per meal will be enough to maximise muscle protein synthesis for both males and females.
What are good sources of protein?
Vegan sources
Source Protein per 100g Pumpkin seeds 30.2 Lentils 24.6 Black beans 21.6 Almonds (raw) 21.2 Tempeh 20.3 Tofu 17.3 Oats (rolled) 16.9 Quinoa (uncooked) 14.1
Meats
Source Protein per 100g Sirloin steak 25g Ribeye steak 25g Rump steak 31g Pork chop 32g Pork loin joint 30g
Poultry
Source Protein per 100g Chicken breast 32g Chicken thigh 28g Turkey breast 35g Duck breast ( 25g
Fish
Source Protein per 100g Cod 24g Haddock 24g Salmon 23g Sea bass 24g Plaice 21g Tuna (canned, drained) 24g Prawns (king) 18g
Dairy
Source Protein per 100g Whole milk 3.3g Semi skimmed milk 3.4 Skimmed milk 3.4g Greek yoghurt (whole) 9.8g Greek yoghurt (0% fat) 11g Cheddar cheese 25g Feta cheese 15g
Protein deficiency
A lack of protein in your diet will lead to a range of health concerns. These can include skin lesions, thin brittle hair and hormone imbalances. On a long-term basis, low protein intake may lead to a condition known as sarcopenia9. This is the loss of muscle mass during the ageing process. A lack of muscle mass in an older person can be quite debilitating as it can prevent day to day activity that can be taken for granted at a younger age.
For healthy individuals, if you are eating a well-balanced diet, it is unlikely you will fall below the RDA of 0.8g/kg.
Side effects of too much protein
Over the years, the safety of high protein intakes has been heavily discussed. Whilst a lot of negative reports of high protein intakes have been proven to be unfounded in healthy individuals1, those with existing health conditions (especially kidney problems) should exercise caution and discuss with a doctor or a registered dietician before starting a high protein diet.
For healthy individuals there is evidence that long term intakes as high as 3.4.4g/kg/d have no detrimental health impacts.10 However, if you take your protein intake up too much and in any way that will prevent you from getting in enough other macronutrients whilst sticking to your calorie allowance may cause problems. For example, if you are having so much protein that you do not have enough calories left for an appropriate amount of carbohydrates, side effects may include constipation, dehydration and bad breath.
Eating a balanced diet with a protein intake optimal for your health and fitness goals (1.2-2-5g/kg/d) will help to reduce side effects and prevent health concerns.
Take Home Message
Protein is essential for health with optimal intakes depending on your goals. The RDA for protein is 0.8g/kg/d. For active individuals this will need to be higher. Those looking to build muscle an optimal intake would 1.6g/kg/d and for maintaining muscle mass whilst dieting a higher intake between 1.4-2.4g/kg/d may be required.