Protein Needs - US Guidelines on Protein and Diet
The Recommended Daily Allowance (RDA) of protein according to U.S. government standards is 0.8 gram per kilogram (2.2 pounds) of ideal body weight for the adult. This protein RDA is said to meet 97.5% of the population's needs.
Adult Male Protein Needs
An adult male who should weigh about 154 pounds, or 70 kilograms, requires about 56 grams of protein daily.
The British Association for the Advancement of Science says 1 gram per kilo of BW.
This is an example of that "science" you speak of.