A High Protein Diet Is More Effective in Improving Insulin Resistance and Glycemic Variability Compared to a Mediterranean Diet—A Cross-Over Controlled Inpatient Dietary Study

Abstract

The optimal dietary pattern to improve metabolic function remains elusive. In a 21-day randomized controlled inpatient crossover feeding trial of 20 insulin-resistant obese women, we assessed the extent to which two isocaloric dietary interventions—Mediterranean (M) and high protein (HP)—improved metabolic parameters. Obese women were assigned to one of the following dietary sequences: M–HP or HP–M. Cardiometabolic parameters, body weight, glucose monitoring and gut microbiome composition were assessed. Sixteen women completed the study. Compared to the M diet, the HP diet was more effective in (i) reducing insulin resistance (insulin: Beta (95% CI) = −6.98 (−12.30, −1.65) µIU/mL, p = 0.01; HOMA-IR: −1.78 (95% CI: −3.03, −0.52), p = 9 × 10−3); and (ii) improving glycemic variability (−3.13 (−4.60, −1.67) mg/dL, p = 4 × 10−4), a risk factor for T2D development. We then identified a panel of 10 microbial genera predictive of the difference in glycemic variability between the two diets. These include the genera Coprococcus and Lachnoclostridium, previously associated with glucose homeostasis and insulin resistance. Our results suggest that morbidly obese women with insulin resistance can achieve better control of insulin resistance and glycemic variability on a high HP diet compared to an M diet.

Beyond bariatric surgery and weight loss medicaments. A systematic review of the current practice in obesity rehabilitative inpatient programs in adults and pediatrics

“…Approximately 65% of the participating subjects were women. The Italian studies were 50% of the total ( 24 – 33 ), while the other weight reduction programs were conducted in the USA ( 34 – 36 ), Norway ( 37 , 38 ), Germany ( 39 , 40 ), Czechia ( 41 ), Brasil ( 42 ), and Taiwan ( 43 ).…”

“…The inclusion and exclusion criteria heavily depended on the context, in particular, studies that took into consideration routine treatments had less specific criteria. Age was chosen as a cut-off for inclusion only in three studies ( 27 , 33 , 35 ) and three studies recruited only women ( 33 , 34 , 41 ). The study design was largely dependent on its aim.…”

“…Studies that were more oriented on experimentation preferred to use a two-arm randomized controlled design ( 25 , 32 , 35 , 40 , 43 ); however, most of the papers involved non-randomized participants, with a high prevalence of longitudinal studies ( 24 , 26 , 27 , 29 , 30 , 34 , 36 , 37 , 39 , 41 , 42 ) of which only three with a control arm ( 28 , 31 , 38 ). Only one study applied a randomized crossover design ( 33 ). Dietary interventions were almost entirely consisting of a low-calorie diet, except for two studies ( 35 , 40 ) in which the diet administered was normocaloric and weight loss was achieved exclusively by increasing physical activity.…”

“…Approximately 65% of the participating subjects were women. The Italian studies were 50% of the total (24)(25)(26)(27)(28)(29)(30)(31)(32)(33), while the other weight reduction programs were conducted in the USA (34)(35)(36), Norway (37,38), Germany (39, 40), Czechia (41), Brasil (42), and Taiwan (43). The setting was named differently, such as "weight disorder inpatient unit, " "rehabilitation clinic, " or "university hospital.".…”

The microbiota composition drives personalized nutrition: Gut microbes as predictive biomarkers for the success of weight loss diets

“…Coprococcus, for example, might exert a positive effect through the production of SCFAs. Moreover, Lachnoclostridium species might metabolize precursors of trimethylamine and its oxide, which negatively regulate glucose metabolism and insulin sensitivity (68). Another study assessed baseline characteristics to predict the postprandial glucose response and revealed that the relative abundance of Faecalibacterium is negatively associated with plasma glucose after the consumption of high-and low-resistant starch (69).…”