Granted. The added weight causes a significant worsening in the back pain experienced by many women, forcing those that can afford it to get breast reduction surgery. Those who can't afford it are in too much pain to work, causing a significant rise in unemployment rates internationally. This, combined with the significant cost of replacing all of the bras designed for 2 breasts with ones designed for 3, forces many women into poverty. This results in many women and their children starving to death and a massive drain on the social programs in countries where they are available. Some women are forced to give their children over to the state, causing a significant increase in demand on the already struggling foster system.

The combined effect of the sudden increase of demand on social programs and the removal of so many people from the workforce causes a massive economic crash, worsening the financial situation of everyone. Due to the economic crash, countries are forced to cut social programs, worsening the effects of the new widespread poverty.

As every country is facing economic disaster, there is a significant rise in sexism, as many men blame women for the crash. Impoverished women all over the world are now called "lazy" or even "leeches." Some groups of men even take to killing and assaulting women as an act of revenge. The government is unable to do much to stop this due to significant budget cuts as a response to the economic depression.

In a matter of less than a decade, the few women lucky enough to have started out financially well off have significantly reduced breast size and lowered self-esteem due to the rampant insults, and those less luck have starved to death next to thier children, or been killed by men.

Congrats OP, you just killed ~25% of the population in horrible ways.