The authors reviewed 15 prospective studies, and following a review of the quality of the data contained within, selected seven of them for analysis. What they found probably shouldn't surprise anybody: if you eat away from home "frequently", you're probably going to weigh more than somebody who eats at home less "frequently". The authors of the review further looked at different types of food sources away from the house, and (surprise again!) found that fast-food outlets had a higher correlation with these negative anthropometric implications than traditional restaurants. It's noted in the article that "other out-of-home foods" are lacking the research to declare correlation between consumption and negative body changes, and suggests more research be undertaken.
While nobody should be surprised by the results of this literature review, it's likely that the restaurant industry will be quick to point out that other factors lead to a healthy lifestyle besides just your choice of eating location, including exercise, lifestyle, genetics, etc. Though the article looked at long-term prospective studies, it did not indicate any other potential sources of anthropometric change besides where the meals were consumed.
Another consideration is that the articles reviewed by the authors range in date published between 1998 and 2011. There have been many changes in the types of food being served "away from the home" over the past 15 years, both for marketing reasons (I'm looking at you fast-food salads) and for legislative reasons (see: BC's Public Health Impediments Regulation dealing with trans fats). Presumably, a prospective study undertaken now and published in 10 years time would show similar outcomes, but perhaps not quite to the same extent.
Policy makers and food-industry regulators should take heed of this research. Though some legislation has been put in place that makes "out-of-home food" more healthy (see above in re trans-fat laws), there is still work to be done to ensure that when people are unable to eat at home for whatever reason, they are not putting themselves at risk of significant health issues.
Source: Dossa, R. A., Nago, E. S., Lachat, C. K., & Kolsteren, P. W. (2014). Association of Out-of-Home Eating with Anthropometric Changes: A Systematic Review of Prospective Studies. Critical Reviews in Food Science and Nutrition, 54(9), 1103-1116.