The #800gChallenge is simply to a tool to guide healthy eating. It provides a metric to evaluate “clean” eating. While it can be used as a nutrition challenge of a specified length, it also can be applied as a daily “challenge” to one’s day-to-day choices for any length of time.
The #800gChallenge does not give the individual specific targets in terms of protein, fat, or carbohydrate grams. That is up to the individual based on their food choices. The 800g is simply the mass of fruits and vegetables consumed in any preparation style – fresh, cooked, frozen, or canned (in water, drained). The specific “rules” developed for applying this as a diet method can be found here.
Why 800 grams? Because Aune et al. (2017) found it was associated with better health outcomes and also meets or exceeds multiple other fruit and vegetable recommendations (e.g., USDA). See more on the “why” and benefits here.
The 800g total is based on the research by Aune et al. (2017), but the diet “rules” should not be interpreted as study findings (e.g., beans are included in the #800gChallenge but Aune et al. did not include them in that study). It also cannot be concluded that 800g is an optimal number for everyone; it is simply a tool to guide healthy eating.
Aune, D., Giovannucci, E., Boffetta, P., Fadness, L.T., Keum, N., Norat, T., … Tonstad, S. (2017). Fruit and vegetable intake and the risk of cardiovascular disease, total cancer and all-cause mortality-a systematic review and dose-response meta-analysis of prospective studies. International Journal of Epidemiology, 46(3), 1029-1056. doi: 10.1093/ije/dyw319