Thinking you want that triple chocolate chip cookie? Think again. Researchers have found that microbes living in your gut have ways of suppressing or increasing your cravings. Choosing between a cookie and an apple can change the population sizes of different of bacteria, as well as what kind of nutrients they absorb.
One study has noted that whilst lack of any essential amino acid from diet would normally result in a strong craving in flies, Acetobacter and Lactobacillus (gut bacteria) can work together to quash this craving. Maybe I should stop feeding my gut bacteria so much sweets…