Diet

A diet was an practice exercised by humans, particularly during the 20th and 21st century, to remove excess fat.

By 2009, there were over a thousand diet pills on the market, most of which were scams to steal people's money. Ms Foster took advantage of this situation, and created Adipose Industries, a company that served to, with the use of a supposed diet pill, give birth to millions of Adipose from human fat cells. They, however, publicly explained it differently: "The Adipose capsule is composed of a synthesised mobilising lipase, bound to a large protein molecule. The mobilising lipase breaks up the triglycerides stored in the adipose cells, which then enter—"

- Adipose Industries

Suzette Chambers, Roger Davey and Stacey Campbell were on the pill, along with one million customers in the Greater London area. After defeating Foster's plan to kill a million people to birth more Adipose, the Tenth Doctor admitted that "as a diet plan, it sort of works." (TV: Partners in Crime)

During the same year, Sylvia Noble attempted to get her father on a macrobiotic diet, but he'd always sneak off to the petrol station to get pork pies. (TV: The Sontaran Stratagem)

When the Third Doctor nearly failed to squeeze through a tight entrance to a tunnel underneath Exxilon, he decided, perhaps jokingly, that he needed to go on a diet. (TV: Death to the Daleks)

Atkins Diet was a diet that, according to Lance Bennett, Donna Noble talked excitedly about. (TV: The Runaway Bride) In the false reality of the Library's Data Core, Donna, when confronted with the notion that it was not real, first complained about that fact that she'd been dieting. (TV: Forest of the Dead)

After not catching a thing and collapsing during the activity, the Sixth Doctor vowed to Peri that he would never fish again; they'd stick to a healthy, vegetarian diet. (TV: The Two Doctors)