First, there is no such thing as ‘ruining your diet’. If you associate certain foods with failure, then this suggests you have some beliefs about food that need to be challenged. 

As for when to snack. Research has found that eating according to your circadian rhythm can affect your body weight, suggesting late night snacking could lead to more weight gain. We don’t know why yet, but high-sugar snacks could interfere with your sleep, as well as the obvious effect on your dental health.

As for daytime snacking? Becoming more in tune with your body’s cues on hunger fullness and thirst – snacking more mindfully – will help. In other words go with your gut.