Data from Nielsen Holdings PLC NLSN, -4.46% and the Food Marketing Institute shows that 70% of grocery shoppers will be buying online in the next five-to-seven years. Previously, Nielsen forecast that a majority of shoppers would purchase groceries online in eight-to-10 years. "Now, the estimated $100 billion spend, which is equivalent to every U.S. household spending $850 online for food and beverage annually, will occur by 2022 or 2024," the group said in a statement. The results come as Amazon.com Inc. AMZN, -1.78% , with its Whole Foods Market acquisition, and Wal-Mart Stores Inc. WMT, -1.02% with its Jet.com purchase, are making an e-commerce grocery push. Nielsen and FMI recommend that grocery retailers rely on a multi-platform approach across both stores and digital channels, consumer data, and improved marketing and promotions to reach customers. The PowerShares Dynamic Food & Beverage Portfolio PBJ, -0.69% is up 6.7% for the past year while the S&P 500 index SPX, -1.11% is up 24.7% for the period.