In April 2019 researchers from the USA published the results of their study to assess the effect of replacing breakfast with a high-fat drink on fat mass, lean mass, percentage of body fat, abdominal fat, resting metabolic rate, fuel utilization, blood lipids and feelings of fullness in overweight and obese adults. A total of 42 healthy adults (21 males, 21 females; average BMI 33 kg/m-2) were involved in the study, with 21 individuals receiving a meal replacement and 21 in a control group. Body measurements were assessed measured and the metabolism rate and fuel utilization assessed. The meal replacement, which contained 70% fat, was consumed once daily. for a period of 8 weeks. Results showed that for both males and females, there was no change in fat mass, lean mass, percentage body fat, or abdominal fat for the meal replacement group versus the control group. There was also no effect on the metabolic rate or fuel utilization in either group. However, the HDL(good)-level was significantly reduced in the meal replacement group for females. It was also noted that the feeling of fullness increased in the afternoon for those consuming the meal replacement. The researchers therefore concluded that despite a high fat content, a meal replacement had no negative impact on lipids and had no effect on body measurements, although there was an increased increased feeling of fullness which may be beneficial for controlling afternoon cravings.
Smith-Ryan AE et al. High-Fat Breakfast Meal Replacement in Overweight and Obesity: Implications on Body Composition, Metabolic Markers, and Satiety. Nutrients. 2019 Apr 17;11(4). pii: E865.