Method for treating high-protein grains with a view to improving the use thereof as food, in particular for animals, these grains being chosen from at least one of the following grains: fava bean ( Vicia fava L.), peas ( Pisum sativum L.), white lupin ( Lupinus albus L.), blue lupin ( Lupinus angustifolius L.) and yellow lupin ( Lupinus luteus L.), characterised by the fact that it comprises the following consecutive steps: (a) using grains of at least one of the aforementioned plant species, with the condition that these grains have a protein and/or starch and/or fat content of a value greater than or equal to that indicated in the table below: Content greater than Nutritional Compounds Protein (g/100g DM) Starch (g/100g DM) Fat (g/100g DM) Fava bean 28 39 Vicia fava L. Peas 22 45 Pisum sativum L. White lupin 35 8 Lupinus albus L. Blue lupin 31 5.5 Lupinus angustifolius L. Yellow lupin 38 5.0 Lupinus luteus L. And, at least one of the compounds of the following group: anti-nutritional factor, crude fibre, neutral detergent insoluble fibres, with a content lower than that indicated in the table below: Species ANF/Crude fibre/NDF Content less than (g/100g DM) Fava bean Tanins 0.3 Vicia fava L. Vicine, convicine 0.5 Alpha-galactosides 2.5 Crude Fibre 10 NDF 18 Peas Tanins 0.01 Pisum sativum L. Alpha-galactosides 5 Crude Fibre 7.5 NDF 18 White lupin Alkaloids 0.1 Lupinus albus L. Alpha-galactosides 10 Crude Fibre 16 NDF 25 Blue lupin Alkaloids 0.2 Lupinus angustifolius L. Alpha-galactosides 9 Crude Fibre 18 NDF 29 Yellow lupin Alkaloids 0.3 Lupinus luteus L. Alpha-galactosides 12 Crude Fibre 18 NDF 29 b) Placing grains of step a) under a minimum pressure of 10 bar, for a duration of more than 10 seconds, until obtaining a temperature higher than 80°C; and/or b bis) heating the grains, for a minimum duration of 15 minutes, preferably from 30 minutes to 2 hours, at a temperature higher than 80°C, preferably between 90 and 150°C. (a) using grains of at least one of the aforementioned plant species, with the condition that these grains have a protein and/or starch and/or fat content of a value greater than or equal to that indicated in the table below: Content greater than Nutritional Compounds Protein (g/100g DM) Starch (g/100g DM) Fat (g/100g DM) Fava bean 28 39 Vicia fava L. Peas 22 45 Pisum sativum L. White lupin 35 8 Lupinus albus L. Blue lupin 31 5.5 Lupinus angustifolius L. Yellow lupin 38 5.0 Lupinus luteus L. And, at least one of the compounds of the following group: anti-nutritional factor, crude fibre, neutral detergent insoluble fibres, with a content lower than that indicated in the table below: Species ANF/Crude fibre/NDF Content less than (g/100g DM) Fava bean Tanins 0.3 Vicia fava L. Vicine, convicine 0.5 Alpha-galactosides 2.5 Crude Fibre 10 NDF 18 Peas Tanins 0.01 Pisum sativum L. Alpha-galactosides 5 Crude Fibre 7.5 NDF 18 White lupin Alkaloids 0.1 Lupinus albus L. Alpha-galactosides 10 Crude Fibre 16 NDF 25 Blue lupin Alkaloids 0.2 Lupinus angustifolius L. Alpha-galactosides 9 Crude Fibre 18 NDF 29 Yellow lupin Alkaloids 0.3 Lupinus luteus L. Alpha-galactosides 12 Crude Fibre 18 NDF 29 b) Placing grains of step a) under a minimum pressure of 10 bar, for a duration of more than 10 seconds, until obtaining a temperature higher than 80°C; and/or b bis) heating the grains, for a minimum duration of 15 minutes, preferably from 30 minutes to 2 hours, at a temperature higher than 80°C, preferably between 90 and 150°C.