Heavy metals prove all too common in meal replacement products, says watchdog group

Soylent has attracted the attention of a consumer advocacy group that claims the meal replacement drink contains levels of lead and cadmium that require a warning

The popularity of meal replacement drinks has been surging in the United States over the past few years, driven by the obesity epidemic and Americans' diminishing amount of leisure time, according to market research firm CB Insights. In Silicon Valley, techies and tech investors alike have embraced the trend. Soylent is the best known meal replacement startup, thanks in part to a 2014 New Yorker feature titled "The End of Food" and a $20m investment round in January 2015, led by storied venture firm Andreessen Horowitz.

This week, the startup made headlines for a different reason after consumer advocacy group As You Sow filed a notice of legal action, alleging that the company's products contain levels of lead and cadmium that would require a warning under California law.