Great find @DavidPS !
Similarly, in a weight loss study conducted with community-dwelling older adults (~70 years old), participants who voluntarily shifted daily protein intake from dinner to earlier meals lost more total weight and more body fat without changing total daily protein intake (51). The researchers concluded that “a more even pattern of protein intake was associated with a greater decline in BMI and abdominal fat”.
In a second study utilizing the same diet protocol, we evaluated the additive and synergistic effects of dietary protein and resistance exercise on body composition changes during weight loss (50). Utilizing a 2 × 2 design, 48 women (BMI ~33; age ~ 46 years) were randomly assigned to one of four treatment groups: low protein, low protein with exercise, higher protein, and higher protein with exercise. Similar to the previous study, the dinner meals were similar across all groups. The primary diet differences were increased protein and reduced carbohydrates at the first two meals in the higher protein groups. After 16 weeks, the higher protein (diet only) group lost 12% more body weight, 18% more body fat, and 25% less lean body mass compared to the low protein group. Consistent with the previous study, 35% of the weight lost for the low protein group was fat-free mass, and 25% for the higher protein group.
The exercise treatment consisted of 5 days/week of walking for 30 min and 2 days/week of resistance exercise (49). After 16 weeks, the higher protein + exercise group lost 46% more body weight, 60% more body fat, and 40% less fat-free mass compared with the low protein + exercise group. This study demonstrated the synergistic effects of dietary protein and exercise to improve body composition during energy restriction for weight loss. Furthermore, the addition of 16 weeks of exercise to the low protein treatment group resulted in the loss of an additional 0.5 kg of body fat compared with the low protein group without exercise, while the addition of exercise to the higher protein group resulted in the loss of an additional 2.9 kg of body fat compared to the diet group without exercise. To the best of our knowledge, this was the first study to demonstrate the interactive effect of dietary protein and exercise on improving body composition in adult women during weight loss.