Detox symptoms can come on you in a short time, but it's more likely to be triggered by what you don't eat than by what you do eat. Some foods can help your body clean itself out, but it's mostly about your body recognizing that its ability to filter out toxins isn't fully utilized just dealing with what you're currently taking in (and not just through food). The likelihood of this also increases if you are taking actions that improve your body's ability to clean out toxins, including exercise. Your system can use the opportunity to address and dispose of toxins that have been stored up until they could be dealt with. That tends to bring the toxins back into your blood stream temporarily, allowing them to cause negative effects until they get filtered out for good. Those effects can vary wildly, but I've heard of headaches, sneezing, soreness, lethargy, acne, runny nose, and others.
The concern is that a suddenly appearing symptom could represent an intolerance to what you're eating, or an illness, or something else entirely. WFHO has a couple of ingredients that a small proportion of people are sensitive to. We can tolerate the discomfort of detox in the name of making our bodies into cleaner, healthier places, but it's important not to label symptoms as detox if they are in fact signs of a different problem that could be causing you harm. For one thing, if you find that you have symptoms that seem to be triggered each time you eat WFHO, then my instinct would be to suspect that you have an intolerance to one or more of the ingredients, and you may need to try a different product.
If you took WFHO as a meal replacement, then you may be experiencing detox if what you normally would have eaten was more of a load on your liver or kidneys. Many, if not most, modern traditional breakfast foods are fairly damaging to our systems, so removing them from your diet can be a good step toward cleaning your system.
So, I guess what I'm saying is that it is entirely possible to have signs of detox, but you should monitor any symptoms you're having. Look for patterns and try to make sure that what you're experiencing really is detox before you dismiss the symptoms as unimportant.