The amount and activity of digestive enzymes is not the same for all people and it does not remain constant. Various factors in daily life can influence how efficiently enzymatic processes occur.
These include, among other things, increasing age, persistent stress, or the regular intake of certain medications. In such phases, the body often has less enzymatic capacity available, even though there has been no change in eating habits.
Many people experience exactly this: meals that were previously well tolerated suddenly lead to feelings of fullness, bloating, or a general sense of heaviness after eating. This is often prematurely classified as "intolerance," although the actual background is more complex.
Digestion is sensitive to external and internal influences. Changes in daily life can therefore be enough to shift the balance of enzymatic processes, even without a fundamental disorder being present.
Many common approaches focus exactly on this point - however, not always where digestion actually begins.