I often hear people say things like "Our bodies can't process sugar" or "I heard that we shouldn't eat gluten " (or meat, dairy, and all sorts of other things). My initial reaction is annoyance, sometimes even anger. But when I step back, it's actually really sad how misinformed the public is about nutrition and health. I think I take for granted the extensive education I've had that allows me to filter these messages.
So let's take a look at what happens when you eat. The food goes in your mouth where your teeth and saliva start to break it down. You then swallow and it goes down your esophagus into your stomach where your stomach churns and mixes the food with gastric juices that help further break the food down into individual particles.
Absorption of the nutrients primarily takes place in your small intestine. From there the carbohydrate, protein and fat molecules are transported via the portal vein to your liver. Your liver is the metabolic command center of your body. It decides where the nutrients go and what purpose they will be used for in your body. Your liver and kidneys also detoxify (I hate to even use this word because it's become associated with diets) non-nutritive substances. Thus, no need (nor effectiveness) for "detox" diets.
The parts of the food that aren't absorbed in your small intestine move on to the large intestine where they formed into feces and excreted as waste. Your large intestine also helps maintain your body's fluid and electrolyte balance. This is one reason why laxatives can be so dangerous, they work via the large intestine can disrupt the body's electrolytes and cause cardiac arrest. (Side note: since laxatives function in the large intestine, they are of absolutely no use for getting rid of calories, as those were already absorbed in the small intestine).
The moral of the story, your body is amazing, and it regulates itself. It can handle all types of foods, and makes up for our "mistakes" in eating. We can relax and trust that when we listen to our body's desires and fuel it adequately, it will take care of the rest.