To "avoid being chosen", people were advised to join the gym.
The campaign has a colourful history, and has even been cited in a court dispute involving a breakaway gym franchise.
Now, the Advertising Standards Authority (ASA) has upheld multiple complaints about the latest ad.
The ad alienated multiple complainants, who called it humiliating, hurtful and offensive.
Club Physical responded that "currently Martians don't exist" so the ads were clearly science fiction, intended to be funny. The firm even compared the ads to Government-run campaigns using shock tactics to deter drink-driving.
The company said a similar aliens-and-fatties promotion a few years ago generated mostly positive feedback.
But one complainant said the latest ad used "vile tactics" and "shaming and bullying techniques" to generate shock.
The ASA's complaints board upheld the complaints, saying the ad was "likely to cause offence to most people as it ridiculed people who were overweight".
Club Physical said it was sorry for any offence caused - but inactivity was deadly and needed to be addressed urgently. Club Physical told the authority that all references to the ad had been removed.
However, a Club Physical video on YouTube with flying saucers above downtown Auckland and an alien declaring "Quick, get the fat ones first" was still online yesterday. It has attracted only 122 views in four years.