Nutritional Considerations During Major Weight Loss Therapy: Focus on Optimal Protein and a Low-Carbohydrate Dietary Pattern

Cardiopulmonary responses to acute exogenous ketosis at rest, and during submaximal and maximal exercise

Nutritional ketosis achieved through various methods in animals and humans has been shown to augment cardiac efficiency and function. However, this response during exercise has not been well characterized. Recreationally active adults (n = 12) completed a double blind, balanced, placebo-controlled, crossover study to examine the effects of bis-octanonyl (R)-1,3-butanediol (BO-BD) ingestion on cardiopulmonary function at rest and during a maximal oxygen consumption (V̇O2max) treadmill test (Bruce Protocol). Participants presented to the testing facility fasted. Capillary blood samples were obtained to measure glucose and beta-hydroxybutyrate (R-βHB) prior to consuming the BO-BD or a calorically matched placebo (PL) beverage. Metabolic and cardiovascular measures were collected every 15-30 min following beverage consumption. Participants began the V̇O2max test 120 min post-beverage ingestion. At rest, capillary R-βHB elevated rapidly after BO-BD ingestion and continued to steadily increase to 2.4 mM prior to the maximal exercise test. During the 120 min rest period, BO-BD increased resting heart rate (HR) (p = 0.001), ventilation (p < 0.001), and V̇O2 (p = 0.002) relative to PL. Although the total time to exhaustion was similar between conditions, V̇O2max was lower after BO-BD (p < 0.001). There were no differences in exercise lactate, RER, respiration, or rating of perceived exertion (RPE) between conditions. Compared to PL, BO-BD rapidly achieves nutritional ketosis, increases resting cardio-respiratory parameters, but somewhat paradoxically decreases peak aerobic exercise oxygen consumption despite achieving similar peak workloads.

Nutrition support whilst on glucagon-like peptide-1 based therapy. Is it necessary?

AIM OF THE REVIEW

Weight loss is a primary goal in the treatment of obesity, but its effect on body composition - particularly fat-free mass (FFM) and skeletal muscle mass (SM) - is of increasing concern. This review examines the effects of antiobesity medications, particularly glucagon-like peptide-1 receptor analogs (GLP-1 RA), on body composition, the risk of sarcopenia, and strategies to preserve muscle mass during pharmacological weight loss.

RECENT FINDINGS

Studies have shown that while GLP-1 RA are effective in reducing fat mass, up to 40% of the total weight loss can come from FFM. However, it is important to distinguish between FFM and SM, as FFM includes nonmuscle components. Resistance training and adequate protein intake can mitigate muscle loss, but the evidence for their efficacy in the context of GLP-1 RA therapy is mixed. If these measures are insufficient to prevent and maintain muscle mass, the use of some nutrients, such as branched chain amino acids, creatine, leucine, omega-3 fatty acids and vitamin D, may be beneficial. Newer pharmacological approaches, such as bimagrumab, a human monoclonal antibody that acts by binding to the activin type II receptor II (ActRII), and other activin or myostatin inhibitors, show promise in preserving muscle mass while promoting fat loss.

SUMMARY

GLP-1 RA therapy for obesity should include resistance training, optimal protein intake and, if needed, specific nutrients and possibly pharmacological interventions to preserve muscle mass. Further research is needed to assess the long-term effects of GLP-1 RA on muscle health and to refine strategies to prevent sarcopenia in patients undergoing pharmacological weight loss.

Illnesses associated with ketosis including diabetic ketoacidosis during very low carbohydrate and ketogenic diets

AIMS

Ketogenic diets are used by individuals with obesity and type 2 diabetes for improved glycaemic control, reduced appetite and weight loss. However, the risks associated with higher ketone levels, including diabetic ketoacidosis (DKA), in individuals with and without diabetes are not well-documented.

MATERIALS AND METHODS

We analysed real world data from a single-centre telemedicine clinic specializing in a very low carbohydrate ketogenic diet (VLCKD) as a lifestyle intervention. Illnesses associated with ketosis (IAK) were defined as beta-hydroxybutyrate (BHB) levels ≥3 mmol/L when patients sought in-person care. We estimated the IAK and DKA incidence rate in individuals with and without type 2 diabetes.

RESULTS

In 72 751 patient-years of follow-up, 86 people had IAK (incidence rate 1.18 per 1000 person-years). In 22 347 patient-years of follow-up of people without diabetes, the incidence rate of IAK was 0.04 per 1000 person-years with no DKA cases. In 50 404 patient-years of follow-up in people with type 2 diabetes (PWD), the incidence rates of IAK and of DKA were 1.69 and 1.01 per 1000 person-years, respectively. In 12 763 person-years of follow-up of PWD using SGLT2-inhibitors, the DKA incidence was 2.90 per 1000 patient-years.

CONCLUSIONS

Very low carbohydrate ketogenic diets are generally safe with low rates of IAK, including DKA, in people with and without type 2 diabetes. The higher incidence of DKA in PWD on VLCKD who are also on SGLT2-inhibitors may be manageable through at-home monitoring of BHB levels.

Investigating nutrient intake during use of glucagon-like peptide-1 receptor agonist: a cross-sectional study

Background

Glucagon-like peptide-1 receptor agonist (GLP-1RA) pharmaceutical interventions have advanced medical treatment for obesity, yet little is known about nutrient intake while using a GLP-1RA. The purpose of this study was to compare nutrient intake while using a GLP-1RA to the Dietary Reference Intakes (DRI).

Methods

A cross-sectional study was conducted in a sample of participants who had been using GLP-1RA for at least one month (N = 69). Participants answered online survey questionnaires and completed a 3-day food record. Descriptive statistics (means, standard deviations) were calculated for all participant demographic characteristics and average 3-day nutrient intakes. Average 3-day nutrient intakes were compared to the DRI using 95% confidence intervals (CI). A Bonferroni correction applied accepted significance at p ≤ 0.00156. One-way ANOVA analysis was conducted to compare the self-reported MyPlate servings to recorded servings from the 3-day food record.

Results

Compared to the DRI reference values, participants consumed adequate amounts of B-vitamins, copper, phosphorus, selenium, and zinc. Participants had insufficient intakes of several key nutrients below the DRI, including fiber (14.5 g; CI: 12-17), calcium (863 mg; CI: 756-970), iron (12.1 mg; CI: 11-13), magnesium (266 mg; CI: 236-297), potassium (2,186 mg; CI: 1,969-2,402), choline (305 mg; CI: 268-342), vitamin A (560 mcg RAE; CI: 469-651), vitamin C (51 mg; CI: 41-61), vitamin D (4 mcg; CI: 3-5), vitamin E (9.6 mg; CI: 8-11), and p < 0.00156. Participants overconsumed % calories from fat (39.9%; CI: 38, 42), and saturated fat (26 g; CI: 26, 26), p < 0.00156. Participants did not meet the daily recommended MyPlate servings for fruit, vegetables, grains, or dairy (p < 0.01). Protein intake (% total calories) was within the AMDR, however based on a g/kg/day, protein intake was significantly under daily needs.

Conclusion

Participants on a GLP-1RA are not meeting the DRI for several vital nutrients through their diet or higher protein needs during weight loss. Patient-centered nutritional guidance is essential to optimize health outcomes and prevent unintended health consequences. Future large-scale studies are needed to assess the replicability of these findings and provide custom nutritional guidance for those on a GLP-1RA medication.

Mitigating muscle loss during weight loss: can nutritional ketosis make a difference? A call for more research

Weight loss (WL) has an important role in managing obesity and type 2 diabetes, but preserving lean body mass (LBM) during WL is essential for maintaining muscle function and metabolic health. Significant WL with incretin mimetic-based therapies, similar to bariatric surgery, raises concerns regarding disproportionate LBM loss, which may lead to physical frailty. Recent analyses have suggested that high adherence to a ketogenic diet may mitigate LBM loss while improving physical function, even with substantial WL. However, more research is needed to understand the mechanisms behind LBM preservation in nutritional ketosis and the role of other lifestyle interventions. Future studies of pharmacological, surgical, and lifestyle-driven WL interventions should also assess LBM, physical function, and frailty. Research in this area is essential for developing strategies that optimize patient outcomes, especially for those who are considering their options for the treatment of obesity.