Larger portions, packages, and tableware lead to higher consumption of food and drink, a Cochrane review has found (Hollands et al., 2015).

The research said that eliminating larger portions from the diet could reduce energy intake by up to 16% (roughly 279 kilocalories a day) among UK adults or by up to 29% (roughly 527 kilocalories a day) among US adults.

Reference

Hollands, G.J., Shemilt, I., Marteau, T.M., Jebb, S.A., Lewis, H.B., Wei, Y., Higgins, J.P.T. & Ogilvie, D. (2015) Portion, Package or Tableware Size for Changing Selection and Consumption of Food, Alcohol and Tobacco: A Cochrane Systematic Review. Cochrane Database of Systematic Reviews. Issue 9. Art. No.: CD011045. DOI: 10.1002/14651858.CD011045.pub2.