Introduction Inthe past 30 years the main goal of nutritional guidance has changed from theprevention of nutritional deficiencies to the prevention of chronic diseasescaused by obesity epidemic (Byers, 1999; McAllister, 2009). Food labels enablesconsumers to compare the nutritional values of food products and make healthy food choices based on the relevant nutrition information(Soederberg-Miller and Cassady, 2015). Nutritional epidemiology, defined as thescience of relations between food choices and population health (Michels, 2003), plays an increasingly important role influencingfood labels policy-making worldwide (Byers, 1999), as it is a vital tool promotinga balanced diet and public health. Nutritional epidemiology is relatively newbranch of the wider epidemiology field, which is the study of the frequency,distribution and determinants of health-related states and events in humanpopulations, and the application of this study to the control of diseases andother health problems (WHO, 2017; Whiteman,2011).

Although abundance of nutritional epidemiology research articles isavailable, their quality is variable as the fundamental criteria for the relationship between cause and effectare often not met, in large part because many dietary factors are weak and donot show linear dose-response relations with disease risk within the range ofexposures common in the population (Byers, 1999). Health care professionals including dietitians areincreasingly required to base their clinical decision-making practice on thebest available evidence. Evidence based medicine (EBM) is the tool that integratesthe best research evidence with clinical expertise and patient values (Sackett et al.

, 2000). The conceptof EBM recognizes ever changing research literature (Steves and Hootman,2004), actively encourage critical thinking, demands the accuracy andprecision of diagnostic tests, and improve quality of care through thecharacterisation  and promotion ofpractices that work and the termination of those that are harmful orunsuccessful (Grayand Pinson, 2003; Levi, 2001). Since relying onpoor quality evidence can lead to harm being caused or limited resources beingwasted (Rosenberg and Donald,1995), in this essay, I will discuss and critically appraise a published study by Mhurchu et al. (2017)entitled “Effects of interpretative nutrition labels on consumer foodpurchases: the Starlight randomised controlled trail” withregards to three main areas: validity, importance, and applicabilityto patients and wider population.