Does Eating Breakfast Aid Weight Loss?

One of the most commonly encouraged dietary recommendations for aiding weight loss and promoting long-term weight control and better health is to always start the day with a healthful breakfast. However, this popular public health mantra is based largely on observational data that does indicate that obese people are generally more likely to skip breakfast than their leaner counterparts. Of course, observational data does not tell us whether this correlation is causal or simply coincidental. And if there is indeed a causal connection between skipping breakfast and obesity, it might well be that metabolic changes that result from body fat accumulation may actually be causing people to be less hungry early in the day. If so, this would suggest that obesity may reduce the desire to eat breakfast rather than skipping breakfast causing people to gain weight. Certainly the association between skipping breakfast and being overweight is well established (1). However, despite this association, there is really little credible evidence from properly-controlled clinical trials to tell us whether or not dietary advice to eat breakfast regularly would actually aid weight loss or impact body weight in the long term.To answer the specific question of whether or not the dietary advice to eat breakfast will aid weight management, Dr. Allison at the University of Alabama and his associates conducted a multi-site, 16-week, randomized controlled trial. These researchers recruited about 300 overweight and obese (BMI: 25 to 40) men and women seeking to lose weight. The subjects were divided into 3 groups that were all given the same dietary advice on how to adopt a healthful weight loss diet. For the control group, no advice was given about eating breakfast. In the two experimental groups, one was instructed to eat breakfast and the other was instructed not to eat breakfast. To limit bias, the researchers made sure that before starting their weight loss diet, the number of subjects in each of the 3 groups contained the same ratio of people who normally ate or skipped breakfast. The subjects in the no breakfast group reported skipping breakfast 92.4% of the time, while the group instructed to regularly consume breakfast reported doing so 93.6% of the time over the next 16 weeks. The results of this largest ever randomized controlled clinical trial to examine the impact of dietary advice to eat or skip breakfast found that such advice had no significant effect on the amount of weight lost (2).The results of this study suggest that public health messages (and certainly specific dietary advice) that people need to regularly eat breakfast in order to lose weight are simply not evidence-based. However, this study did not examine the long-term impact of eating or skipping breakfast on long-term weight control. It is likely that what people eat (and perhaps also when during the day they chose to eat it) will impact satiety levels throughout the day. It may also impact their ability to keep weight off after it is lost.Another recent study examined the impact of either a high-protein low-carbohydrate breakfast or a much higher-carbohydrate breakfast but a smaller dinner on weight management. In this study, 193 middle-aged, sedentary and obese people were fed isocaloric diets. Those who received the larger, higher-carbohydrate breakfast lost an average of 13.5 kilograms (kg) while those who ate the smaller high-protein breakfast meals but a larger dinner meal lost an average of 15.1 kg. This difference was not significant.However, after the controlled dietary intervention period ended, these researchers followed the subjects for another 16 weeks. During this follow-up period, the group who had become habituated to eating the larger, higher-carbohydrate breakfast and smaller dinner meals during the first 16-week intervention period continued to lose an average of another 6.9 kg. By contrast, those who had been eating the smaller high-protein breakfast but larger diner meals regained 11.3 kg.The researchers also measured reported hunger levels and blood ghrelin levels over the entire 32-week observational period. They found evidence that the subjects who were eating the smaller high-protein breakfast and larger dinner meals regained most of the weight they lost during the calorie-restricted diet perhaps in part because their ghrelin (hunger hormone) levels were higher than in the group that had become accustomed to the larger, higher-carbohydrate breakfast (3).Bottom Line: The results of these two studies suggest that instructing people to either eat or not eat breakfast will likely have little or no impact on their ability to initially lose weight. However, the composition and timing of food intake may well impact hunger levels and the ability to keep off lost weight. More research is needed as to what would be optimal dietary advice for losing excess body fat stores and keeping them off long term.By James J. Kenney, PhD, FACNSources:

1. Mesas AE, et al. Selected eating behaviors and excess body weight: a systematic review. Obesity Rev 2012;13:106-35.
2. Dhurandbar EJ, et al. The effectiveness of breakfast recommendations on weight loss: Am J Clin Nutr doi: 10.3945/ajcn.114.089753.
3. Jakubowicz D, et al. Meal timing and composition influence ghrelin levels, appetite scores, and weight loss maintenance in overweight and obese adults. Steroids.2012;77:323-31.