Dieters is the forth episode of Season four and the 49th episode of The Most Extreme. This episode aired on November 29, 2005 on the Animal Planet channel.
- Number 10 Hummingbird: The hummingbird is number 10 in the countdown of the most extreme dieters because it has to eat every two hours. It has to eat every 2 hours because it's body burns a lot of energy by hovering over flowers to get energy-rich nectar. In addition it visits 1,000 flowers a day so it uses a lot of energy and that's why it's two hours away from starvation. Time without eating food: 2 hours.
- Number 9 Shrew: needs to eat vast amounts just fuel its fast metabolism; can starve to death in only a few hours; loses heat incredibly fast thanks to its small size; one species of shrew has to eat three times its own weight of food every day. Time without eating food: a few hours.
- Number 8 Camel: it doesn't eat for two weeks by burning all the fat in its hump; they carry their supplies on their back, a portable pantry full of fat, it's hump; will chew and eat anything. Time without eating food: 2 weeks.
- Number 7 Weddell Seal: has to put on at least 180 kilograms when pregnant because she won't get another meal for 3 weeks; baby puts on 90 kilograms in only 6 weeks for insulation from the water; in 6 weeks, the mom loses those 180 kilograms. Time without eating food: 3 weeks.
- Number 6 Emperor Penguin: dad goes for more than 120 days without food huddled together with others to protect their young and keep it warm until its hatches; only thing the male has to eat is a little snow to stay off dehydration but is no use when the males are hungry; manages to lose 45% of his body weight; both parents manage 16 meals in 5 months of incubating the egg and raising the baby. Time without eating food: 3 months.
- Number 5 Right Whale: swallow 15,000 krill in a single gulp; a quarter of all this food will be converted to blubber needed for its journey; won't eat a thing for the next four months once it leaves it's hunting grounds on a 10,000 kilometer trip; loses 40% of its body weight once it gives birth. Time without eating food: 5 months.
- Number 4 Honeypot Ant: in droughts, the colony relies on the workers for food by storing their food supply in them; can survive six months without food. Time without eating food: 6 months.
- Number 3 Bear: can go for seven months without food; pack away 65,000 calories per day in the summer and can gain about 13 kilograms every week in which 80% is pure fat needed to survive the long cold winter. Time without eating food: 7 months.
- Number 2 Salmon: can go for nine months without food because it only focuses on reproduction and there is little food in the streams and their digestive system will just shut down; keep a supply of sugars within its body because it powers its muscles; lose up to 30% of its body weight; die after reproduction but they release nutrients that enrich the spawn. Time without eating food: 9 months.
- Number 1 Tick: can go for than a decade between meals and really pig out when they get a chance to eat; can drink 600 times its own weight in blood; some species can wait 18 years between meals and survives but shutting down its metabolism so that it burns very little energy; only a whiff of carbon dioxide snaps the tick out of it. Time without eating food: 18 years.