Eating two slices of pizza is unlikely to reverse the progress you’ve made on a diet for weight loss.
‍Research shows that even when overeating in excess over multiple days, any weight gain is temporary and tends to come from water retention, not fat mass.
However, studies show that a “black or white” mentality around food can encourage repeated episodes of overeating.
Thinking two slices of pizza will “ruin” their diet, people may “fall off the wagon” and feel less motivated to continue following a balanced diet.