If we're getting technical, the weight of a human does vary throughout the day. Generally, while asleep, your mass decreases. You're always gradually losing mas

If we're getting technical, the weight of a human does vary throughout the day. Generally, while asleep, your mass decreases. You're always gradually losing mass as you inhale O2 and exhale CO2. You're also losing mass as you exhale moisture, and you may also sweat. Thus an adult human male (who sleeps, say, 10pm to 6am) is less likely to break a lego brick at 2am than at midnight and more likely than at 4am.