Consumption of red meat has been associated with fat gain (and weight gain) because of its high energy and fat content. Even though the role of fat intake as a causative factor for obesity recently has been seriously questioned, and rightly so, red meat still is a food that’s on the forbidden or avoid list of most diet plans. And while there are studies showing an association between meat intake and obesity [1-3], there are also studies not showing this [3-5]. And when digging deeper in the data, many of the studies that have reported a significant association with meat intake and fat gain / obesity have several flaws that invalidate their conclusions…. Meat consumption and long term weight change One of the latest, and largest study to date on this topic, concluded : “Total meat consumption was positively associated with weight gain in men and women, in normal-weight and overweight subjects, and in smokers and nonsmokers. With adjustment for estimated energy intake, meat intake of 250 g/d (eg, one steak at approximately 450 kcal) would lead to a 2-kg higher weight gain after 5 years compared to the same diet with less meat. Positive associations were observed for red meat, poultry, and processed meat”. This is a pretty bold statement! However a closer look at its methodology and data reveals major weaknesses: First; usual dietary intake was assessed only at baseline and not during the subsequent years. It is well recognized that peoples food habits often change over time. And it doesn’t take a rocket scientist to understand that in order to track changes over time, at least two measurements are required. And the baseline food intake assessment was done with questionnaires, which are infamous for being inaccurate [7-9]. Using a methodology that begs the question “how bad is good enough” will obviously not provide very reliable data . Second; in several centers, participants who consumed more meat actually had less weight gain, whereas those with lower meat consumption had higher weight gain. Despite this, and despite the very large number of participants (about 103,000 men and 270,000 women), the researchers behind this study lumped them all together in the statistical analysis. Also, the assessment of physical activity, which is strongly related to food habits , was done via self administered questionnaires, which do not accurately reflect objective physical activity or fitness data [11, 12]. Therefore, the stated adjustment for a possible influence of physical activity on the observed weight change, cannot be relied upon. Third; the researchers reported an effect based on a combination of meat sources, but their analyses indicate that after exclusion of participants with chronic diseases and those likely to misreport energy intake at baseline, the following was found: - red meat is not the villain in the association of meat intake and weight gain - the association with poultry was attenuated - processed meats were the strongest predictor of weight gain This indicates that processing, or factors associated with consumption of processed foods are involved rather than meat per se. Fourth; and probably the most important shortcoming is that the observed weight changes may be due to changes in either lean body tissue or fat mass or both . Meat is a high-quality source of protein for building and maintaining lean body mass. Consequently, the noted association between meat intake and weight change may partly be due to gain of lean body mass in participants with high meat intake. It is well known that dietary protein plays a major role in developing and maintaining lean tissue mass in the body during growth in infancy, through adulthood while dieting, and particularly in preventing loss of lean body tissue and sarcopenia in elderly individuals over 50 years of age . The loss of lean body mass is a particular problem in individuals over 60 years of age. In older individuals, a higher intake of high quality protein, such a red meat, helps to prevent loss of lean body tissue, resulting in better muscle strength, bone density, and physical functioning . Thus, it is interesting that the association between meat intake and weight gain was stronger in participants that were over 45 years of age. An alternative interpretation of this finding is that a higher intake of red meat preserves lean body mass (including muscle mass), and that the weight gain seen with higher intakes of red meat is not fat gain. This interpretation of the results is congruous with other studies showing that an increase in protein intake from meat and other sources enhances diet induced fat loss [16-19], contributes to weight control [20, 21] and prevents gain of body fat [21, 22]. Thus, studies that don’t measure body composition don’t tell much about the role of meat for body fat control. Because of all these methodological flaws, the conclusion that “a decrease in meat consumption is recommended for body weight management and improvement of health” is totally misleading. So if you come across any anti-meat proponents who bring up this study to support their position, take them out to dinner and get them a huge juicy steak!