📝 Detailed Answer
I've been on diets myself. More than once, I've held back all week only to binge on the weekend and feel dizzy and miserable. Speaking from experience, cheat days are a double-edged sword.
On the plus side, constant restriction makes the body perceive an 'emergency,' sharply lowering metabolism. Occasionally replenishing nutrients can revive metabolic rate. It also eases psychological pressure, giving you staying power for the long haul.
The downsides are more pronounced. Sudden overeating in a state of Spleen Deficiency (biheo, 脾虛) — where spleen function is weakened — can seriously damage the digestive organs. Undigested food accumulates, easily generating Phlegm-Fluid (dameum, 痰飮), which are internal waste products. Above all, once the appetite control switch is broken, it's truly hard to reset.
There's no one-size-fits-all answer. For those with strong digestion and willpower, it can be a proper rest; for those with weak stomachs, it becomes poison.
That's why I suggest not blindly scheduling a 'cheat day,' but first examining your individual constitution and current digestive state. Let's explore together what level of 'cheating' your body can handle.