ROOTFUL tool
Protein and fibre calculator: your daily needs
Protein is calculated per kilogram of body weight, not in portions. Fibre has a European reference that almost nobody reaches. Enter your weight and goal to get both figures, plus how far you are from them.
An estimate for healthy adults, based on the ranges used in the nutrition literature (0.8 to 2.4 g of protein per kilogram, depending on activity and goal) and on the EU reference of 25 g of fibre a day. People with kidney or liver conditions should discuss protein intake with their doctor.
Why protein is calculated per kilogram
“How much protein do I need?” has no answer in servings, because the need depends on how much you weigh and what you ask of your body. A 55 kg woman who walks and a 55 kg woman who lifts weights four times a week have different needs, and the difference is not small.
The recommended daily amount of 0.8 g per kilogram, the one that appears on most labels, is the minimum threshold for avoiding deficiency in a sedentary adult. It is not the target for someone who trains or is losing weight: it is the floor, not the goal.
The ranges we used
- Sedentary, maintenance: 0.8 to 1.0 g/kg. Enough not to lose muscle mass.
- Moderately active: 1.2 to 1.6 g/kg. Exercise three to five times a week.
- Strength training: 1.6 to 2.2 g/kg. The range used in the sports nutrition literature for building muscle mass.
- Weight loss: 1.6 to 2.4 g/kg. In a calorie deficit, higher protein helps preserve muscle mass, so that the loss comes from fat.
What this means in food
- 100 g chicken breast: about 31 g protein
- 150 g Greek yoghurt: about 15 g
- 100 g salmon: about 20 g
- 100 g cottage cheese: about 11 g
- One large egg: about 6 g
- 100 g cooked lentils: about 9 g
- 100 g cooked chickpeas: about 9 g
- 30 g almonds: about 6 g
Seen this way, the numbers suddenly become realistic: 120 g of protein a day doesn't mean powders, it means every meal has a clear source of protein in it.
Why we split it across meals
The body can't use an unlimited amount at once for muscle protein synthesis. Research suggests it is more effective to spread your intake in servings of about 0.3 to 0.4 g/kg at each meal than to have almost all of it at dinner. That is why the calculator also shows you the figure per meal; it is usually the part that surprises people.
Fibre: the number almost nobody reaches
The reference value in the European Union is 25 g of fibre a day for adults. Actual average intake in Europe is generally well below this threshold, and with a modern diet based on refined products, the gap is easy to explain.
The calculator's estimate starts from the servings of vegetables and fruit you entered and adds a baseline for the rest of your diet. It is approximate by design (an apple doesn't provide as much as a serving of lentils), but it is enough to see which range you are in.
How to increase fibre without bloating
The classic mistake is jumping from 12 g to 30 g in a day. Your gut flora needs time to adapt, and a sudden jump means bloating and discomfort. Increase by about 5 g a week and drink more water alongside it: fibre without fluid does exactly the opposite of what you want.
The sources with the best ratio are legumes, oats, flax and chia seeds, pears and apples with the skin on, and cruciferous vegetables. Soluble fibre, the kind that forms a gel (inulin, glucomannan, the beta-glucans in oats), is also the one that contributes most to the feeling of fullness.
From the ROOTFUL ritual
How much protein per day, by body weight
A 70 kg adult who exercises 3 to 5 times a week needs 84 to 112 g of protein a day, which is 1.2 to 1.6 g per kilogram. For fibre, the EU reference intake is 25 g a day regardless of weight.
| Weight | Sedentary 0.8 to 1.0 g/kg |
Moderately active 1.2 to 1.6 g/kg |
Strength training 1.6 to 2.2 g/kg |
Weight loss, keeping muscle 1.6 to 2.4 g/kg |
|---|---|---|---|---|
| 50 kg | 40 to 50 g | 60 to 80 g | 80 to 110 g | 80 to 120 g |
| 60 kg | 48 to 60 g | 72 to 96 g | 96 to 132 g | 96 to 144 g |
| 70 kg | 56 to 70 g | 84 to 112 g | 112 to 154 g | 112 to 168 g |
| 80 kg | 64 to 80 g | 96 to 128 g | 128 to 176 g | 128 to 192 g |
| 90 kg | 72 to 90 g | 108 to 144 g | 144 to 198 g | 144 to 216 g |
| 100 kg | 80 to 100 g | 120 to 160 g | 160 to 220 g | 160 to 240 g |
| 110 kg | 88 to 110 g | 132 to 176 g | 176 to 242 g | 176 to 264 g |
Split the total across your meals: 0.3 to 0.4 g per kilogram at each meal works better than eating most of it at dinner. People with kidney or liver conditions should discuss protein intake with their doctor.
Frequently asked questions
How much protein should I eat a day?
It depends on your weight and activity: 0.8 to 1.0 g per kilogram for a sedentary person, 1.2 to 1.6 g if you move regularly, 1.6 to 2.2 g for strength training and 1.6 to 2.4 g if you are losing weight and want to keep your muscle mass.
How many grams of fibre a day are recommended?
The reference value in the European Union is 25 g a day for adults. Actual average intake in Europe is generally below this threshold.
Can I eat too much protein?
For healthy adults, intakes within the ranges above are considered safe in the nutrition literature. People with kidney or liver conditions should, however, discuss protein intake with their doctor.
How much protein is in a chicken breast?
About 31 g per 100 g. For comparison: 100 g of salmon has about 20 g, 150 g of Greek yoghurt about 15 g, a large egg about 6 g, and 100 g of boiled lentils about 9 g.
Why does it matter how I split protein across meals?
The body cannot use an unlimited amount at once for muscle protein synthesis. It is more effective to spread intake in portions of about 0.3 to 0.4 g per kilogram at each meal than to eat nearly all of it at dinner.
How do I increase fibre without getting bloated?
Gradually, by about 5 g a week, and with more water alongside. Jumping suddenly from 12 to 30 g in a day is the usual reason for bloating.
