07/04/2017 (Tue) 14:40:21
There are two reasons why eating raw potato is a bad idea, though it's not actually poisonous or anything
Firstly, starches, while soluble in water, dissolve slowly, as it's made of long molecules that stick together well. This is especially true for amylopectins (branched varieties of starch), and potato (or wheat as well) contain over 75% amylopectins, as opposed to unbranched amyloses which don't stick together as well. Enzymes generally need to have macromolecules dissolved to break them down, because they work by using their active spot to cleave molecules. If they can't reach the sites where they can work, they can't work. Cooking dissolves starch (increasing the temperature speeds up the process), while baking initiates breakdown of starches non-enzymatically (carbohydrates, as most biomolecules, are thermally unstable and will rapidly start to decompose as temperature goes further and further above the boiling point of water). So, instead of digesting the starch in stomach and small intestine and absorbing it into the bloodstream as glucose, most of the starch will enter the colon. Nowadays it's fancy to call that "dietary fibre" (which also includes closely related celluloses, which humans can't digest at all due to lacking a cellulase enzyme required to break down the different bonds between glucose units), and parade it as healthy because it somehow "aids digestion" (well, it does feed your gut flora), but basically it just means that you are decreasing your food's energy value, and increasing the amount of food you give to your gut flora. You'll shit more and fart more and feel bloated.
Secondly, as a tuber, potato contains natural defense against being eaten by pests. In case of potato, this is the poisonous glycoalcaloid solanine (a strong pesticide present in all nightshades), which is generally only present in potatoes that have been already munched on by pests or exposed to light (in which case they'll appear green due to production of chlorophyll), so you don't need to worry about this one much, but it also contains several protease inhibitors, which block the proteases (protein-digesting enzymes) in your stomach. So, you additionally won't be able to digest proteins properly (potato itself doesn't contain much proteins, but whatever you ate with potatoes might), again leading to the undigested proteins being delivered tot your gut flora in the colon. Protein waste products generally smell bad due to presence of amines and sulphur compounds, further turning the aforementioned copious amounts of fecal products into biohazard.