How the Calculation Works

The Nutrient Reference Values for Australia and New Zealand give two kinds of figure. The calculator uses the RDI and leaves out the EAR, which is here for context:

• Recommended dietary intake (RDI). This level meets the needs of nearly all (97 to 98%) healthy people in an age and sex group.
• Estimated average requirement (EAR). Half the people in a group need less than this level, so it sits below the RDI.

These are the rates per kg of body weight, per day:

• Women aged 19 to 70: EAR 0.60 g, RDI 0.75 g
• Men aged 19 to 70: EAR 0.68 g, RDI 0.84 g
• Women over 70: EAR 0.75 g, RDI 0.94 g
• Men over 70: EAR 0.86 g, RDI 1.07 g

The sum is your weight in kilograms multiplied by the rate. For a woman aged 40 who weighs 72 kg, the RDI rate gives 54 g a day and the EAR rate gives 43 g a day. For a man aged 45 who weighs 90 kg, the same rates give 76 g and 61 g a day. These examples are arithmetic only.

Protein a Day by Body Weight

This table applies the RDI rates for adults aged 19 to 70, rounded to the nearest gram.

Read the higher rows with care. Dividing the published daily figures by the rates gives a body weight of about 61 kg for women and 76 kg for men. The Nutrient Reference Values estimated requirements using fat-free mass (body weight without fat), and they do not say how to apply the rates at a much higher body weight. So your result may be well above the published figure, and a GP or dietitian can tell you which figure suits you.

Checking Protein Against Your Energy

Grams per kg do not take your energy intake into account, so a second check helps. The Nutrient Reference Values suggest at least 15% of energy from protein, to help meet other nutrient needs, and a prudent upper level of 25%. healthdirect quotes a wider 10% to 35%, so sources differ on the range.

Protein has 17 kJ per gram. For example, at a daily target of 7,600 kJ (about 1,820 calories), 15% is 1,140 kJ, or 67 g of protein, and 25% is 1,900 kJ, or 112 g. That target is an example only, not a suggested intake. If you are working to a weight loss target, use the daily target at a healthy weight from the calorie deficit calculator, not the gap. The BMR calculator estimates your daily energy use, and the article on how many calories a day to lose weight gives more detail. If your figure is in calories, change it with the kilojoules to calories converter.

Does More Protein Help With Weight Loss?

A high-protein diet can help you feel fuller for longer, which may help some people lose weight, alongside balanced nutrition from all the food groups and daily exercise (healthdirect). Outcomes vary between individuals. The picture has limits:

• No separate figure. The reference values above are for healthy people. The 15% to 25% range is not necessarily a recommendation for weight loss diets.
• Smaller energy targets. A smaller energy target can leave protein short. The article on working out your macros for weight loss shows an example at 5,000 kJ (about 1,200 calories).
• Protein still has energy. Protein eaten on top of what your body needs is either removed as waste or stored as weight gain.
• Exercise. People who exercise vigorously do not need extra protein (Better Health Channel). Australian sources differ here, as some people might need more during periods of physical activity (healthdirect). The Australian Institute of Sport gives 1.2 to 1.6 g per kg a day for athletes in heavy training. That figure is for athletes, so this calculator does not use it. Extra protein on its own does not build muscle, as the article on does muscle weigh more than fat explains.
• Very high intakes. A very high protein diet can strain the kidneys and liver. There is limited information about the longer-term effects of intakes above 25% of energy.
• Kidney disease. People with chronic kidney disease should follow the protein levels their health team recommends.

Getting Your Protein From Food

Most Australians already get enough protein from food, eating small amounts at every meal is a good way to meet the daily requirement, and protein shakes, powders and supplements are unnecessary for most Australians' health needs (Better Health Channel). Good sources include lean meats, poultry, fish, eggs, reduced-fat dairy foods, nuts, seeds, legumes and tofu. To compare them, read high protein, low calorie foods compared. For meal ideas, read about the best breakfast for weight loss, the best foods for weight loss and a weight loss meal plan. For shakes, read weight loss shakes and how they differ from protein shakes.

Protein is one part of a healthy diet built on the five food groups. For the energy side of weight loss, read what a calorie deficit is and how to work out yours and how to lose weight: a realistic guide.

Regular physical activity matters too. Australia's guidelines for adults suggest 30 minutes or more of moderate to vigorous physical activity on most days, plus muscle-strengthening activities on 2 or more days a week. For ideas, read how many steps a day to lose weight.

Frequently Asked Questions

How do you calculate protein intake?

Multiply your body weight in kilograms by the grams per kg rate for your age and sex, listed under How the Calculation Works on this page. The rates are higher after age 70. For example, a man aged 75 who weighs 80 kg works out at 1.07 g x 80 kg, or 86 g a day. This is arithmetic only.

How much protein a day do you need to lose weight?

The Australian protein figures on this page do not include a separate amount for weight loss. A high-protein diet may help some people lose weight alongside a healthy diet and physical activity, but protein still counts towards your energy intake. Outcomes vary between individuals, so a GP or dietitian can help you work out what suits your health and your eating pattern.

Is 2 g of protein per kg too much?

It can be. 2 g per kg sits at the limit a 1997 FAO working party recommended for the general population, and well above the Australian recommended intakes of 0.75 to 1.07 g per kg. The Australian reference values also suggest an upper level of 25% of energy. If you want to eat this much, speak with your GP or a dietitian first.

Is 200 g of protein too much for a day?

Yes, on Better Health Channel advice. Some fad diets promote 200 to 400 g a day. Even 200 g is about 2.5 to 4.3 times the published daily intakes of 46 g to 81 g on this page, which is arithmetic only. A very high protein diet can also prompt loss of calcium, which can increase your risk of osteoporosis. Please talk to a GP or dietitian first.

Is 100 g of protein a day enough?

Yes, against the published daily figures, the highest being 81 g for men over 70. The per kg rates can pass 100 g, for example from about 94 kg for men over 70 and about 120 kg for men aged 19 to 70. Below about 6,800 kJ (about 1,630 calories) a day, 100 g passes 25% of energy. This is arithmetic only, and a GP or dietitian can advise you.

How much protein is in common foods?

Per 100 g as eaten, grilled chicken breast has about 30 g of protein, tuna canned in water about 26 g, firm tofu about 13 g and boiled lentils about 7 g (Australian Food Composition Database). Brands and cuts differ, so check the nutrition panel on packaged foods. The article on high protein, low calorie foods compared lists 20 foods.

References

• Eat for Health (NHMRC). Nutrient Reference Values: protein. https://www.eatforhealth.gov.au/nutrient-reference-values/nutrients/protein
• Eat for Health (NHMRC). Nutrient Reference Values: macronutrient balance. https://www.eatforhealth.gov.au/nutrient-reference-values/chronic-disease/macronutrient-balance
• Eat for Health (NHMRC). Nutrient Reference Values: introduction. https://www.eatforhealth.gov.au/nutrient-reference-values/introduction
• healthdirect. Protein. https://www.healthdirect.gov.au/healthy-living/food-and-nutrition/protein
• healthdirect. Chronic kidney disease. https://www.healthdirect.gov.au/conditions/kidney-and-urinary-problems/chronic-kidney-disease
• Better Health Channel (Victorian Government). Protein. https://www.betterhealth.vic.gov.au/health/healthyliving/protein
• Better Health Channel (Victorian Government). Dietary fat. https://www.betterhealth.vic.gov.au/health/healthyliving/dietary-fat
• Better Health Channel (Victorian Government). Weight management services. https://www.betterhealth.vic.gov.au/health/HealthyLiving/weight-management-services
• Australian Institute of Sport. Isolated protein supplement. https://www.ausport.gov.au/ais/nutrition/supplements/group_a/sports-foods2/isolated-protein-supplement2/what-is-it
• Food Standards Australia New Zealand. Australian Food Composition Database, Release 3. https://www.foodstandards.gov.au/science-data/food-nutrient-databases/afcd
• Eat for Health (NHMRC). Australian dietary guidelines 1 to 5. https://www.eatforhealth.gov.au/guidelines/australian-dietary-guidelines-1-5
• Australian Government Department of Health, Disability and Ageing. Recommendations for adults (18 to 64 years). https://www.health.gov.au/topics/physical-activity/24-hour-movement-guidelines-for-all-australians/recommendations-for-adults-18-to-64-years

This page is general information only and does not replace individual medical advice. Please speak with a registered Australian healthcare practitioner about your own circumstances.