ASN Reviews Look for the Key to Healthy, Sustainable Weight Loss and Weight Management
The World Health Organization (WHO) reports that “obesity has reached epidemic proportions worldwide, with at least 2.8 million people dying each year from overweight or obesity.” In the United States, the Centers for Disease Control and Prevention (CDC) estimates that more than 40% of the adult population suffers from obesity, which puts them at higher risk of heart disease, stroke, type 2 diabetes and certain cancers.
Unfortunately, losing weight and maintaining a healthy weight isn’t easy. A 2020 review published in The BMJ, for example, analyzed the effect over time of 14 named diets on weight loss and cardiovascular risk factors, working with 121 eligible trials and 21,942 patients. According to the study results, “most macronutrient diets, over six months, result in modest weight loss and substantial improvements in cardiovascular risk factors.” However, the authors also found that “at 12 months, the effects on weight loss and improvement in cardiovascular risk factors largely disappeared.”
The key to healthy, lasting weight loss and weight management remains elusive. Nevertheless, nutrition researchers around the world continue to conduct studies in search of a viable solution, often publishing their results in ASN journals so that other researchers can further their research and that health care providers and public health professionals can apply their results in practice. Below are highlights from the four ASN reviews, exploring the link between nutrition and healthy weight loss and weight management.
Influence of protein intake, race and age on responses to weight reduction intervention in obese women, Current developments in nutrition, April 2017
The goal of healthy weight loss is to achieve a weight that promotes optimal physical function. Weight loss, however, can lead to the loss of lean muscle mass and a corresponding loss of physical function. In response, ASN member Connie W. Bales et al. conducted a six-month randomized controlled trial to compare the effects of a high-protein diet of 1.2 grams of protein per kilogram of body weight versus a diet with the recommended dietary allowance of 0.8 grams of protein per kilogram of body weight. Specifically, the authors looked at the effect of diets on physical function and lean muscle mass in 80 obese women aged 45 to 78. The results of the study “support the feasibility of implementing a balanced, high-protein diet for the reduction of obesity.” Nevertheless, the authors found that “the hypothesis that the high-protein weight loss group would achieve greater improvements in function and lean body mass was not supported by a significant group effect.” In light of these findings, the authors believe that “future studies with larger numbers of participants are warranted in both men and women, and particularly in older age groups.”
The effectiveness of breakfast recommendations on weight loss: a randomized controlled trial, The American Journal of Clinical Nutrition, June 2014
Observational evidence suggests an association between breakfast consumption and lower body weight; however, this does not rule out the possibility that people who eat breakfast tend to weigh less due to other factors associated with breakfast. In response, Emily J. Dhurandhar et al. conducted a 16-week randomized controlled trial in 309 otherwise healthy overweight and obese adults aged 20 to 65 years. The authors compared weight change in a control group with weight change in two experimental groups: one was told to eat breakfast and the other was told to skip breakfast. . According to the authors’ findings, “a recommendation to eat or skip breakfast for weight loss was effective in changing self-reported breakfast eating habits, but contrary to widely held views, it did not have no discernible effect on weight loss”. The authors recommend that future research “assess whether more specific recommendations regarding meal timing and quantity or meal composition might improve weight loss outcomes.”
Meal frequency and timing are associated with changes in body mass index in Adventist Health Study 2, The Food Diary, July 2017
ASN member Hana Kahleova et al. analyzed data from more than 50,000 men and women ages 30 and older who participated in the Adventist Health Study 2 to determine the relationship between meal frequency and timing and BMI. The results of their study suggest that “eating less frequently (and not snacking), eating breakfast, and eating the largest meal in the morning may be effective long-term preventative tools against weight gain.” The study results also demonstrated that participants who generally had the longest overnight fasts (18 hours or more) were more likely to have a lower BMI compared to participants who had shorter overnight fasts. Although meal habits emphasizing eating less frequently, eating breakfast, and fasting for a longer period at night were associated with lower BMI, the authors noted that some people, especially older adults with chronic conditions, might need to choose meal habits that are more likely to promote weight gain.
Is the glycemic index important for weight loss and obesity prevention? Review of evidence on ‘fast’ versus ‘slow’ carbs, advances in nutrition, August 2021
Popular diets such as the Paleo and Keto diets emphasize eating low glycemic index foods. The question is, Do diets that emphasize low glycemic foods actually help people lose weight and maintain a healthy weight? To answer this question in depth, Glenn A. Gaesser et al., member of the ASN. reviewed 35 relevant observational cohort studies, with data from 1,940,968 adults. In addition, the authors reviewed the results of 30 meta-analyses of relevant randomized controlled trials. The authors found that “data from observational cohort studies show no consistent association between BMI and dietary glycemic index.” Additionally, their review of randomized controlled trials provided “little support for the idea that low-glycemic diets are superior for weight loss.” An explanation of the authors’ conclusions can be rooted in how glycemic index values are calculated. The authors argue that “the glycemic index is an imprecise measure of a food’s glycemic response when applied to foods in a meal.”
If you are currently studying the link between nutrition and healthy weight loss and weight management, please consider publishing your research findings in one of the four ASN journals. We will ensure that your research is quickly disseminated around the world so that we can continue to build our knowledge in this critical area of nutrition research.