Here’s important new information for all weight-loss dieters: limiting consumption of sugar and starchy carbs to the evening meal could be a crucial determinant of successful fat loss and long-term weight maintenance.
A research group at the Hebrew University of Jerusalem fed 63 randomly assigned obese police officers (BMI >30) assigned to one of two groups either a reduced-calorie diet providing carbohydrates throughout the day or a reduced-calorie diet with carbohydrates eaten mostly at dinner.
The group that consumed most of their carbs (e.g., bread, corn, legumes, pasta, potatoes) in the evening lost more body fat and enjoyed healthier levels of blood markers linked to reduced risk of cancer, diabetes, and heart disease.
A Hormonal Dynamic Duo
The idea of studying the effect of a reduced-calorie diet with carbohydrates eaten mostly at dinner came from studies of other cultures that tend to practice fasting. Fasting individuals abstain from eating and drinking from dawn to sunset, thus automatically limiting all carbohydrate intake to dinner. Research studies found that that two key satiety-related and energy-sensing hormones in the body were favorably affected by this pattern of carbohydrate consumption.
Specifically, limiting carbohydrate-rich food consumption to the evening meal during fasting led to changes in daytime hormonal levels of leptin and adiponectin that favor body fat loss as well as improved levels of inflammatory markers in the blood, including C-reactive protein, TNF-α, and IL-12. Study investigators found greater reductions in abdominal circumference, body fat mass, and body weight in volunteers on the experimental diet compared to those in the control group.
Leptin, known as “the master satiety hormone,” communicates adipose tissue status to receptors in the brain. Leptin helps regulate hunger, satiety, and food intake and it’s healthy functioning is intimately tied to insulin levels and sensitivity.
Adiponectin, a hormone made primarily in fat cells, plays a critical role in energy regulation and in fat and carbohydrate metabolism. It is widely considered to be the link between insulin resistance, metabolic syndrome, and obesity . Adiponectin has been shown to reduce blood levels of sugar and fats, to improve insulin sensitivity, and to exert a systemic anti-inflammatory effect.
Diet studies have shown that during periods of weight-loss, leptin levels typically decline. As leptin concentrations fall, satiety levels tend to be reduced and dieters begin to eat more food and regain lost weight. Thus, any dietary manipulation, such as limiting intake of daily carbohydrate-rich foods to the dinner meal, tends to sustain higher daytime leptin levels and therefore could help dieters maintain their weight loss over time.
What You Need To Know
In the Israeli study, volunteers who consumed most of their carbs during dinner had higher concentrations of leptin and adiponectin throughout the day when compared to a control group that distributed their carbs across breakfast, lunch, and dinner. This helped the carbs-at-dinner group experience greater satiety during waking hours while it improved their weight-loss and weight maintenance and led to healthier blood levels of insulin, cholesterol, and triglycerides.
Helpful hint: Try using a handful of nuts, as the study participants did, in place of such high-carb foods as breads, cereals, potatoes, rice, and snack chips, to help cut carb intake during the day. Nutrient-rich nuts are a good source of essential fats, protein, magnesium, and vitamin E.
Sources:
http://www.ncbi.nlm.nih.gov/pubmed/21475137
https://www.paleopharm.com/nighttime-carbs-promote-weight-loss/
Robert Haas, MS, is a world-renown sports nutrition consultant, NY Times #1-bestselling author, and nutraceutical product developer. He is the CEO of www.paleopharm.com, a blog devoted to nutraceutical solutions for fitness, weight loss, and healthy aging.
