Why protein targets are set per kilogram
Protein needs scale with body size, which is why every credible recommendation is written as grams per kilogram of body weight rather than a single number. A 60 kg runner and a 100 kg rugby player have very different requirements, even with the same goal.
The ranges in this calculator follow the guidance used by sports dietitians: around 0.75 to 1.2 g per kg for general health, 1.2 to 1.6 g per kg for endurance training, 1.6 to 2.2 g per kg for building muscle, and 1.8 to 2.4 g per kg when dieting, where higher protein helps you hold on to muscle while calories are low.
Hitting the target in real food
A target of 140 g sounds abstract until you translate it into meals. A chicken breast is roughly 35 g of protein, a tin of tuna about 27 g, three eggs around 19 g, and a 250 g pot of Greek yoghurt about 25 g. Spread across four meals, 140 g becomes four servings of about 35 g each, which is very achievable.
The hard part is knowing where you actually stand by mid-afternoon. That is where tracking earns its keep: once you can see a running total, adjusting dinner to close the gap becomes trivial.
