The Short-Term Effect of Whey Compared with Pea Protein on Appetite, Food Intake, and Energy Expenditure in Young and Older Men

Animal and plant-based proteins have different postprandial effects on energy expenditure, glycemia, insulinemia, and lipemia: A review of controlled clinical trials

Dietary proteins have been shown to stimulate thermogenesis, increase satiety, and improve insulin sensitivity in the short and long term. Animal-based proteins (AP) and plant-based proteins (PP) have different amino acid profiles, bioavailability, and digestibility, so it seems to have various short- and long-term effects on metabolic responses. This review aimed to compare the findings of controlled clinical trials on postprandial effects of dietary Aps versus PPs on energy expenditure (EE), lipemia, glycemia, and insulinemia. Data are inconclusive regarding the postprandial effects of APs and PPs. However, there is some evidence indicating that APs increase postprandial EE, DIT, and SO more than PPs. With lipemia and glycemia, most studies showed that APs reduce or delay postprandial glycemia and lipemia and increase insulinemia more than PPs. The difference in amino acid composition, digestion and absorption rate, and gastric emptying rate between APs and PPs explains this difference.

Postprandial effects of dietary protein source on metabolic responses, appetite, and arterial stiffness indices in overweight and obese men: the study protocol for a randomized crossover clinical trial

BACKGROUND

Different dietary protein sources are supposed to have various effects on metabolic responses and arterial stiffness in the postprandial period. This study aims to assess the postprandial effects of dietary protein sources, including animal-based protein (AP) and plant-based protein (PP), as part of a high-protein breakfast on appetite response, energy metabolism, and arterial stiffness in overweight and obese men.

METHODS

This acute randomized crossover clinical trial will be conducted at the Persian study research center at Imam Reza Hospital, affiliated with the Mashhad University of Medical Sciences, located in the northeast of Iran. Forty-six healthy overweight, and obese men aged 18-60 years will be enrolled based on the eligibility criteria. The subjects will complete two interventions (high-protein AP and PP meals) with 1 week washout period. The primary outcome will be the acute effect of the two test meals on appetite response, energy metabolism parameters, including resting metabolism rate (RMR), diet-induced thermogenesis (DIT), and substrate oxidation (SO), and arterial stiffness indices, including pulse wave velocity (PWV) and pulse wave analysis (PWA). The secondary outcomes include changes in lipemia, glycemia, and insulinemia.

DISCUSSION

The findings of this study will provide novel insight regarding the acute effects of different protein sources on energy metabolism, appetite, and arterial stiffness as a significant cardiovascular disease (CVD) risk factor. It will help dieticians develop effective and efficient meal plans to improve weight reduction and maintenance in overweight/obese individuals.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials; code: IRCT20211230053570N1; registered on February 10, 2022.

Protein Source Influences Acute Appetite and Satiety but not Subsequent Food Intake in Healthy Adults

BACKGROUND

Although current recommendations encourage plant-based dietary patterns, data is limited as to whether the equivalent substitution of animal-based protein-rich foods with plant-based versions impacts ingestive behavior.

OBJECTIVE

To compare higher-protein preloads, varying in protein source, on appetite, satiety, and subsequent energy intake.

METHODS

Thirty-two adults (Age: 25±1y; Body Mass Index (BMI): 24.2±0.5kg/m) randomly consumed 250kcal, protein-preload beverages (24g protein), varying in protein source (whey, soy, pea protein isolates (WHEY, SOY, PEA) or micellar casein (CAS)) each morning for 3 acclimation days/preload. On day 4, participants completed a 4-h clinical testing day in which the respective preload was consumed followed by blood sampling and questionnaires every 30min for appetite and satiety. An ad libitum lunch was provided 4-h post-preload. On day 5, participants consumed the respective preload at home followed by an ad libitum breakfast 30min afterwards. For normally-distributed data, repeated-measures analysis of variance (ANOVA) or Friedman non-parametric test were utilized to compare main effects of protein source on study outcomes. Post-hoc pairwise comparisons using least significant differences (LSD) were then performed.

RESULTS

CAS (-3330±690mm*240min) and PEA (-2840±930mm*240min) reduced 4-h appetite vs. SOY (-1440±936mm*240min; both, P<0.05). WHEY was not different (-2290±930mm*240min). CAS (3520±84pg/ml*240min) and PEA (3860±864pg/ml*240min) increased 4-h PYY concentrations vs. SOY (2200±869pg/ml*240min; both, P<0.05). WHEY was not different (3870±932pg/ml*240 min). No differences in ad libitum energy intake were observed.

CONCLUSIONS

CAS and PEA, but not WHEY, elicited greater acute changes in appetite and satiety vs. SOY in healthy adults, supporting that not all protein sources are equivalent. This trial is registered at clinicaltrials.gov (NCT03154606).

Comparative Assessment of the Acute Effects of Whey, Rice and Potato Protein Isolate Intake on Markers of Glycaemic Regulation and Appetite in Healthy Males Using a Randomised Study Design

Global protein consumption has been increasing for decades due to changes in demographics and consumer shifts towards higher protein intake to gain health benefits in performance nutrition and appetite regulation. Plant-derived proteins may provide a more environmentally sustainable alternative to animal-derived proteins. This study, therefore, aimed to investigate, for the first time, the acute effects on glycaemic indices, gut hormones, and subjective appetite ratings of two high-quality, plant-derived protein isolates (potato and rice), in comparison to a whey protein isolate in a single-blind, triple-crossover design study with nine male participants (30.8 ± 9.3 yrs). Following a 12 h overnight fast, participants consumed an equal volume of the three isocaloric protein shakes on different days, with at least a one-week washout period. Glycaemic indices and gut hormones were measured at baseline, then at 30, 60, 120, 180 min at each visit. Subjective palatability and appetite ratings were measured using visual analogue scales (VAS) over the 3 h, at each visit. This data showed significant differences in insulin secretion with an increase in whey (+141.8 ± 35.1 pmol/L; p = 0.011) and rice (−64.4 ± 20.9 pmol/L; p = 0.046) at 30 min compared to potato protein. A significantly larger total incremental area under the curve (iAUC) was observed with whey versus potato and rice with p < 0.001 and p = 0.010, respectively. There was no significant difference observed in average appetite perception between the different proteins. In conclusion, this study suggests that both plant-derived proteins had a lower insulinaemic response and improved glucose maintenance compared to whey protein.

Appetite control: hormones or diet strategies?

PURPOSE OF REVIEW

Appetite control results from metabolic, behavioral, and environmental factors that influence hunger and the desire to eat. We summarize the latest advances in the hormonal and nutritional strategies to control appetite and reduce hunger.

RECENT FINDINGS

The fed-hunger-state is regulated by central and peripheric hormones, which modulate energy balance. Leptin, insulin, ghrelin, peptide YY (PYY), and other gut-derived peptides represent the main appetite controllers. The role of orexins, obestatin, and liver-expressed antimicrobial peptide 2 has been uncovered recently. New insights have demonstrated the role of hippocampal activity as a possible mechanism of action. Glucagon-like peptide 1 (GLP1) receptor agonists are well known agents controlling appetite. Association of GLP1 receptor agonist, PYY, or glucose-dependent insulinotropic polypeptide agonists have been tested as new approaches. Appetite-control hormones have also risen as factors involved in the efficacy of bariatric procedures. High-protein, ketogenic diet, and intermittent fasting have been described as nutritional strategies to reduce appetite, although the physiological mechanism and long-term safety remains unclear.

SUMMARY

Appetite control has been an important target for the treatment of obesity and associated disorders. New studies have demonstrated promising adoption of dietary approaches, hormone-based drugs, and bariatric surgery to control energy intake. Further research will establish a significant association, benefits, and safety of these new therapies.