Written by Chrystal Moulton, Staff Writer. Consuming a protein enriched high carb breakfast while dieting reduced weight loss 5.9 times as much as a low carbohydrate group in a 32 week study.
In the current study, researchers wanted to determine if the composition and timing of meals had an impact on weight loss, weight regain, and appetite.
One-hundred and ninety-three people were recruited from outpatient clinics (female= 115, male= 78). Participants were adults aged 20-65 years old, overweight or obese (body mass index (BMI) of 25-37 kg/m2), non-diabetic, and had normal thyroid, kidney, and liver functioning. Individuals were randomized to one of two treatment diets:
- A low carbohydrate diet consisting of low-calorie meals and a low carbohydrate breakfast.
- A high carbohydrate and protein enriched breakfast diet consisting of low-calorie meals but with a protein enriched breakfast that was supplemented with a dessert item like cookies, cake, ice cream, chocolate, donuts, or chocolate mousse.
Subjects were assigned to either diet plan for 16 weeks (the intervention period) during which they were monitored and weighed every 4 weeks. After the intervention period, individuals were instructed to maintain the assigned for another 16 weeks (the follow-up period weeks 16-32). Check-ups were maintained every 4 weeks during the follow-up period as well. Blood samples were taken at baseline, week 16, and week 32 to assess fasting glucose, insulin, lipids, and a hormone called ghrelin, which signals us to eat. Appetite questionnaires to assess hunger and satiety were also given at the time blood samples were taken. Food cravings were evaluated 2 days before the start of the treatment diet, at week 16, and week 32.
Table 1a. Results for high carbohydrate protein enriched diet group
| Weight (kg) | Fasting glucose (mg/dl) | Fasting Insulin(μU/ml) | Total cholesterol (mg/dl) | Triglycerides (mg/dl) | |
| Baseline | 91.2±9.8 | 94.4±7.0 | 21.7±3.6 | 211.8±17.6 | 174.4±17.6 |
| Week 16 | 77.6±9.0 | 86.2±5.6 | 12.6±3.4 | 189.1±10.6 | 140.8±10.9 |
| Week 32 | 70.6±8.7* | 84.2±4.6* | 8.9±3.9* | 179.2±11.1* | 122.6±9.7* |
Table 1b. Results for low carbohydrate diet group
| Weight (kg) | Fasting glucose (mg/dl) | Fasting Insulin(μU/ml) | Total cholesterol (mg/dl) | Triglycerides (mg/dl) | |
| Basline | 90.4±9.2 | 94.6̉±7.4 | 21.7±3.6 | 212.3±19.8 | 174.5±22.6 |
| Week 16 | 75.2±8.1 | 85.1±6.7 | 13.9±4.8 | 188.6±13.2 | 134.9±7.9* |
| Week 32 | 86.9±9.7 | 95.5±4.9 | 23.69±3.8 | 190.8±18.2 | 174.5±20.9 |
*value differs significantly between groups (p<0.001)
At the end of the trial, participants in the high carbohydrate and protein-enriched diet continued to lose weight through follow-up at week 32 while individuals in the low carbohydrate diet regained weight originally lost during week 16. Weight change during the follow-up period was significantly linked to cravings for sweets (r=0.24, p=0.004), carbohydrates (r=0.2, p=0.02), fast foods (r=0.25, p=0.003), and general cravings (r=0.22, p=0.007). At week 32, researchers also observed a significant positive correlation between body weight and insulin (r=0.61, p<0.0001). Ghrelin levels were significantly lower in the high carbohydrate group at week 16 and 32 compared to both baseline and the low carbohydrate group (p<0.0001). Hunger scores were also significantly lower and satiety scores significantly higher in the high carbohydrate group (p<0.0001).
Overall, researchers found that a high carbohydrate protein enriched breakfast diet resulted in continued weight-loss and higher satisfaction compared to the low carbohydrate diet. Researchers believed that the inability of the low carbohydrate group to maintain weight loss after the intervention period was influenced by lower satiety, increased cravings and ghrelin levels.
Source: Jakubowicz, Daniela, et al. “Meal timing and composition influence ghrelin levels, appetite scores and weight loss maintenance in overweight and obese adults.” Steroids 77.4 (2012): 323-331.
© 2011 Elsevier Inc. All rights reserved.
Posted May 15, 2014.
Chrystal Moulton BA, PMP, is a 2008 graduate of the University of Illinois at Chicago. She graduated with a bachelor’s in psychology with a focus on premedical studies and is a licensed project manager. She currently resides in Indianapolis, IN.
References:
- Jakubowicz D et al. Meal timing and composition influence ghrelin levels, appetite scores and weight loss maintenance in overweight and obese adults. Steroids. 2012 Mar 10;77(4):323-31.
