Gourmet Cells (グルメ細胞 Gurume Saibō) are special, highly adaptive cells first discovered and harvested from the Gourmet Jellyfish by the "Bishokushin" Acacia 605 years ago. The cells have extreme regenerative and strength-enhancing qualities, such that when implanted into the cells of another living thing they can enhance it in various ways. When Gourmet Cells are implanted into an ingredient, for instance, its flavor improves drastically, though it may become more powerful and difficult to capture as well.
Similarly, when a human successfully adapts Gourmet Cells into their body, they gain overwhelming life force and power. Enhancements common to many implantees generally include: extremely increased physical strength, speed, general athleticism, stamina, endurance & senses; it is also possible to gain the ability to project a terrifying 'Intimidation' aura. As long as calories are available, the Cells also grant incredible regenerative power. This amazing vitality granted to a Gourmet Cell user is often reflected in their appearance, as the vast majority of the (mostly male) users possess incredibly muscular physiques. A few, such as Jiro, Mansom, and Chin Chinchin are even capable of releasing more of their power to become monstrously muscular giants.
More exotic enhancements are also possible through Gourmet Cells, however. They can physically mutate the user to generate a wide variety of outright inhuman abilities or grant superhuman senses. Examples include: Sunny's ultra-sensitive prehensile hair, Coco's poison generation, incredible vision & advanced use of synaesthesia, Tommyrod's compound eyes & remote control of limbs through insect ganglia, and Midora's use of blending & camoflauging with the environment. Gourmet Cells also seem to increase the compatibility and effectiveness of transplants (as in the case of Grinpatch's multiple arms and Elg's Heraku body) and symbiotic relationships between organisms (as with Tommyrod and his internally-bred army of insects).
An individual's Gourmet cells 'evolve' when they consume delicious foods that suit them and the 'tastes' of the cells; this enhances the strength of the user and their abilities. They can also evolve as a response to harsh new environments, instantly creating adaptations which allow the user to survive. Training one's Gourmet Cells to adapt to a variety of such environments is an integral part of training to survive in the Gourmet World.Because of the incredible and wide-ranging abilities of the Cells (and in particular their ability to increase fighting strength), many prominent Bishokuya, Saiseiya, chefs, IGO members & criminals have them. Many of these, such as the members of the Bishokukai, seek out new and rare ingredients specifically to increase their fighting strength.
Implanting the Cells into the body carries risks, however. If an individual is not compatible with the Cells at the implantation stage they may gain no power, or even die. Gourmet Cells also have extremely high energy demands, so users must frequently consume large amounts of delicious food, lest the cells begin uncontrollably devouring the their body at the cellular level. So far only Toriko, Starjun and Midora are stated to have been born with their Gourmet Cells (although in Toriko's case he appears to have red and blue gourmet cells), potentially avoiding some of the drawbacks faced by implantees.
The greatest advantage afforded by Gourmet Cells is the Appetite Energy they manifest internally. Versatile and highly powerful, mighty predators can externalize this energy by drawing out their overwhelming desire to devour prey. The energy can then be used to generate a variety of powerful effects. However, the ability to manipulate appetite energy is not an automatic consequence of Gourmet Cell infusion. Even very powerful individuals with strong Gourmet Cells are only able to semi-consciously manifest a degree of Appetite Energy on the instinctual level at best. Truly mastering the energy's incredible power requires its conscious manipulation and a taxing degree of mental control.
While all of these qualities of Gourmet Cells make them extremely powerful and useful, it has been shown that they do have limitations. Their strength and regeneration-enhancing qualities are dependent on the user's calorie intake and their mental state and fortitude. Mental training in disciplines such as Food Honor can make a vast difference in how effectively and efficiently the Cells expend energy. Sufficiently powerful techniques can also simply exceed the powers of an individual's Gourmet Cells, such as when Elg's Cells (which were boosted in regenerative power through his fusion with the Heraku) were nonetheless overwhelmed by Brunch's continuous electrical attacks.
According to Chichi, these manifestations that are known as "Appetite Devils". Whenever a person with Gourmet Cells approach an ingredient that is beyond what they can comprehend, these Devils go berserk, manifesting themselves outside of their user's body and completely taking control as Chichi stated that before the Four Heavenly Kings could even make a judgement as to what ingredient was presented to them, the Devils have already gone wild and manifested themselves.