8 p.m. on 5, 8, ‘‘The Biggest Loser’’ — The losers of a trivia challenge with the theme of childhood obesity must stay in a room filled with junk food, soda and video games for 4 1/2 hours — the amount of time the average youngster spends watching television. The show’s resident pediatrician, Dr. Joanna Dolgoff, visits the three young contestants’ homes to guide their families toward healthier choices. After weigh-in, the players vote on who goes home in the new episode ‘‘Cut the Junk.’’

8 p.m. on 6, ‘‘How I Met Your Mother’’ — When Robin (Cobie Smulders) discovers that Barney (Neil Patrick Harris) never formally asked her father for her hand in marriage, she insists he do so before announcing their engagement. Ted (Josh Radnor) tries to keep his own feelings in check by getting deeply involved in the wedding planning in the new episode ‘‘Band or DJ.’’ Jason Segel and Alyson Hannigan also star.

8 p.m. on SYFY, ‘‘Continuum’’ — In this new sci-fi police procedural, City Protective Services officer Kiera Cameron (Rachel Nichols, ‘‘Criminal Minds’’) is transported from 2077 to deal with eight of the world’s deadliest terrorists who managed to slip through a time warp on the eve of their execution. Trapped in present-day Vancouver, however, Kiera gains a fresh and unsettling perspective on her futuristic society. Tony Amendola and Stephen Lobo also star.

9 p.m. on 6, ‘‘2 Broke Girls’’ — What was supposed to be a weekend getaway for two at a cabin in the woods takes an awkward turn when Max, Caroline and Andy (Kat Dennings, Beth Behrs, Ryan Hansen) all wind up there. Garrett Morris, Matthew Moy and Jonathan Kite also star in the new episode ‘‘And the Bear Truth.’’

9 p.m. on SYFY, ‘‘Being Human’’ — Season 2 of the hit series ended with Aidan (Sam Witwer) buried alive as punishment from vampire leader Mother, Sally (Meaghan Rath) lost in a state of limbo and Josh’s (Sam Huntington) plot to kill his Maker Ray backfiring, endangering Nora (Kristen Hager) instead. New and returning guest stars this season include Mark Pellegrino as Bishop, Aidan’s vampire mentor, and Amy Aquino as Donna, a witch whose spells are sought out to help find Sally.