A method of producing a sealed package of a food product pourable into a tube of packaging material; the method comprising the steps of: - feeding said tube along an axis; - moving at least one pair of first jaws and one pair of second jaws cyclically and alternately along respective sealing paths (G, G') parallel to said axis, and along respective repositioning paths (H, H') along which said first and second pair of jaws (8, 8') move with respect to said tube; said first and second pair of jaws (8, 8') comprising first and second sealing members (16, 17; 16', 17') respectively; - moving said first jaws and second pair of jaws (8, 8'), as they travel along the respective sealing paths (G, G'), into a closed position in which the respective said first and second sealing members (16, 17; 16', 17') grip said tube and respectively form, at different times, a first and a second seal (9a, 9b) sealing the tube and defining respective opposite ends of said package; - moving said first pair of jaws and second pair of jaws (8, 8'), as they travel along the respective repositioning paths (H, H'), into an open position, in which said respective first and second sealing members (16, 17; 16', 17') are detached from said tube; - acquiring a desired value of a quantity related to the weight of a said package; and - forming said second seal at a first distance, which is a function of said value, from said first seal; said first distance being measured parallel to said axis; the method being characterized by comprising the step of adjusting a second distance, crosswise to said axis, between said second sealing members (16', 17') of said second pair of jaws, on the basis of at least one of a first parameter relating to the viscosity of said food product, and a second parameter relating to the output rate of said packages, and after said first sealing members (16, 17) of said first pair of jaws have formed said first seal, and before said second sealing members (16', 17') of said second pair of jaws form said second seal. - feeding said tube along an axis; - moving at least one pair of first jaws and one pair of second jaws cyclically and alternately along respective sealing paths (G, G') parallel to said axis, and along respective repositioning paths (H, H') along which said first and second pair of jaws (8, 8') move with respect to said tube; said first and second pair of jaws (8, 8') comprising first and second sealing members (16, 17; 16', 17') respectively; - moving said first jaws and second pair of jaws (8, 8'), as they travel along the respective sealing paths (G, G'), into a closed position in which the respective said first and second sealing members (16, 17; 16', 17') grip said tube and respectively form, at different times, a first and a second seal (9a, 9b) sealing the tube and defining respective opposite ends of said package; - moving said first pair of jaws and second pair of jaws (8, 8'), as they travel along the respective repositioning paths (H, H'), into an open position, in which said respective first and second sealing members (16, 17; 16', 17') are detached from said tube; - acquiring a desired value of a quantity related to the weight of a said package; and - forming said second seal at a first distance, which is a function of said value, from said first seal; said first distance being measured parallel to said axis;