High-carbohydrate Low-fat Diet Research Articles

Investigation of Skeletal Muscle Mitochondrial Function Following an Ultramarathon: A Case Study in Monozygotic Twins

The primary objective of this case study was to investigate the changes in skeletal muscle mitochondria that occur in response to a 100-km ultramarathon in monozygotic twins. Secondarily, we sought to determine if periodically consuming a low-carbohydrate, high-fat diet (LCHFD) during training would affect these changes. To accomplish these objectives, one pair of male monozygotic twins ran 100 km side-by-side on treadmills. During 8 weeks of training leading up to this event, twin 1 (T1) and twin 2 (T2) consumed a calorie and macronutrient-matched, high-carbohydrate diet, with the exception of 2 consecutive days per week for the final 4 weeks where T2 consumed a calorie and protein-matched LCHFD. Training load was matched between the subjects, most of which they completed together. The subjects were extremely well-matched in VO2 max (61.2 and 60.3 ml/kg/min), BMI (20.4 and 20.6 kg/m2), and body mass (62 and 61.9 kg). During the 100-km run, food and fluid intake were matched, as well as the pace of the run. The run took 16 hours and 3 minutes to complete. Blood draws and muscle biopsies from the vastus lateralis were collected 4 weeks prior to the run, as well as 4- and 52-hours post-run. During the last 4 weeks of training, T2 lost an average of ~1 kg of body weight (BW) over the two days of LCHFD each week (comparing BW of 4 consecutive Mondays to Wednesdays, p=0.02), which was regained two days after reintroduction of carbohydrate, consistent with fluctuating glycogen levels. Though T2 trained with periodically low glycogen levels, respiratory-exchange ratio was no different from T1 throughout the 100-km run. Four hours post-run, state 3, uncoupled, and fatty acid-supported mitochondrial respiration were reduced in T1 by 22.3%, 34.1% and 25.7%, respectively, and by 28.4%, 49.4% and 39.9% in T2, which was associated with a decrease of 15-20% in citrate synthase (CS) activity. Both twins exhibited decreases in mitochondrial complex proteins, though this was more marked in T2. Blood CPK, CRP, and AST levels were also elevated post-run. Possibly the most novel finding from this study was that 52 hours post-run, respiratory capacity, mitochondrial proteins, CS activity and blood markers showed signs of rapid recovery. It is currently unclear by what mechanism mitochondrial respiration and content was reduced 4 hours post-run, or how it recovered in 2 days. Interestingly, maximal mitochondrial ROS production (glutamate, malate and succinate-supported) was decreased post-run at both timepoints but was increased compared to baseline with the addition of ADP (12.5 μM – 100 μM). This suggests that the mitochondria were less sensitive to ADP-induced reductions in ROS. Neither diet resulted in better preservation of mitochondrial function 4-hours post-run, though T2 showed some signs of supercompensation 52 hours-post run. This study is valuable because it provides evidence of an acute reduction in mitochondrial content and function following ultra-endurance activity, followed by rapid recovery. This study was approved by the Brigham Young University Institutional Review Board and conformed to the principles of human experimentation set by the Declaration of Helsinki.

The Influence of Nutrition on Adiponectin-A Narrative Review.

The adipose tissue is an active endocrine organ which synthesizes and secretes a variety of adipokines, including adiponectin with its anti-inflammatory properties. Its expression is influenced by numerous factors such as age, sex, body weight and adipose tissue content. However, dietary factors, i.e., diet structure and the percentage of individual nutrients and products, are very important modulators. Beneficial dietary habits are the Mediterranean diet, DASH diet, diet based on plant products and diet with reduced energy value. Moreover, the share of individual products and nutrients which increase the concentration of adiponectin is worth noting. This group may include monounsaturated fatty acids, polyunsaturated omega-3 fatty acids, dietary fiber, polyphenols, alcohol and milk products. Conversely, dietary ingredients which have a negative effect on the concentration of adiponectin are typical components of the Western diet: saturated fatty acids, trans fatty acids, monosaccharides and disaccharides, and red meat. Furthermore, a diet characterized by a high glycemic index such as a high-carbohydrate low-fat diet also seems to be unfavorable. Due to the fact that available knowledge should be systematized, this study aimed to summarize the most recent research on the influence of dietary factors on the concentration of adiponectin.

Exercise and Nutritional Strategies to Promote Weight Loss: A Narrative Review

Obesity has historically been thought to simply be related to an imbalance between energy intake and expenditure. Weight loss recommendations have traditionally focused on reducing energy intake, maintaining either a high-carbohydrate low-fat diet or vice versa, and increasing physical activity typically through low to moderate intensity exercise. More recently, genetic, physiological, and behavioral factors have also been found to play a significant role in the etiology of obesity. For this reason, the prevention and management of obesity through implementation of different types of exercise and diet intervention programs, behavioral interventions, and/or medical interventions are at the forefront of obesity research. As a result, we are beginning to see a paradigm shift from traditional weight loss and management approaches to personalized diet and exercise strategies. This purpose of this narrative review was to overview: 1.) the effects of physical activity on weight loss; 2.) the effects of diet and cardiovascular exercise on weight loss; 3.) the effects of high protein diet with resistance-exercise on weight loss; and, 4.) behavioral factors that contribute weight loss and maintenance.

A Ketogenic Low-Carbohydrate High-Fat Diet Increases LDL Cholesterol in Healthy, Young, Normal-Weight Women: A Randomized Controlled Feeding Trial.

Ketogenic low-carbohydrate high-fat (LCHF) diets are popular among young, healthy, normal-weight individuals for various reasons. We aimed to investigate the effect of a ketogenic LCHF diet on low-density lipoprotein (LDL) cholesterol (primary outcome), LDL cholesterol subfractions and conventional cardiovascular risk factors in the blood of healthy, young, and normal-weight women. The study was a randomized, controlled, feeding trial with crossover design. Twenty-four women were assigned to a 4 week ketogenic LCHF diet (4% carbohydrates; 77% fat; 19% protein) followed by a 4 week National Food Agency recommended control diet (44% carbohydrates; 33% fat; 19% protein), or the reverse sequence due to the crossover design. Treatment periods were separated by a 15 week washout period. Seventeen women completed the study and treatment effects were evaluated using mixed models. The LCHF diet increased LDL cholesterol in every woman with a treatment effect of 1.82 mM (p < 0.001). In addition, Apolipoprotein B-100 (ApoB), small, dense LDL cholesterol as well as large, buoyant LDL cholesterol increased (p < 0.001, p < 0.01, and p < 0.001, respectively). The data suggest that feeding healthy, young, normal-weight women a ketogenic LCHF diet induces a deleterious blood lipid profile. The elevated LDL cholesterol should be a cause for concern in young, healthy, normal-weight women following this kind of LCHF diet.

An Intravenous 100-mL Lipid Emulsion Infusion Dramatically Improves Myocardial Glucose Metabolism Extinction in Cardiac FDG PET Clinical Practice.

Physiological myocardial accumulation of FDG impairs the diagnosis of inflammatory/infectious or tumoral myocardial detection by FDG PET/CT. We prospectively evaluated the addition, 3 hours before imaging, of an intravenous 100-mL lipid emulsion infusion (Intralipid) to a high-fat, low-carbohydrate diet (HFLCD) for at least 2 meals followed by a fast of at least 6 to 12 hours in patients referred for the diagnosis of myocardial inflammation, endocarditis, cardiac or paracardiac masses, intracardiac device, or prosthetic valve infections. Data of 58 patients consecutively included (28 Intralipid patients, 30 controls with HFLCD alone) were compared. FDG uptake in normal myocardium was scored from 0 (complete myocardial suppression) to 3 (high diffuse uptake). Myocardial maximal, peak, and mean SUV and the rate of interpretable images according to the clinical indication were measured. Compared with controls, Intralipid infusion significantly improved the rate of score 0 (89% vs 63%, P = 0.021), of interpretable images according to the clinical indication (100% vs 72%, P = 0.0047) and decreased all myocardial SUV values (eg, SUVmax median, 1.9 [interquartile range, 1.7-2.5] vs 3.1 [interquartile range, 2.3-4.1]; P < 0.001). A lipid emulsion infusion in addition to HFLCD better suppresses cardiac glucose metabolism than HFLCD alone.

Establishing a proof of concept for the effects of low-carbohydrate, high-fat diet (LCHFD) and physical activity on body composition in type 2 diabetes

Overweight and obesity are both a risk factor for developing and exacerbating type 2 diabetes (T2D). While the most common diet used to treat overweight and obesity focus on high-carbohydrate, low-fat, energy deficit diets, recently, low-carbohydrate, high-fat diets (LCHFD) have become popular in targeting obesity. This proof-of-concept study attempted to determine if an LCHFD could improve body composition variables, or if a concurrent treatment of LCHFD and physical activity would create an interference effect in individuals with T2D. Overweight and obese with T2D (n = 39) were assigned into either a 16-week combined physical activity and LCHFD group (ConG), LCHFD-only group (DieG) or control group (NonG). No statistically significant (p > 0.01) changes were found in body mass in the ConG (2.0%, F = 0.039, P = 0.846) and DieG (2.5%, F = 0.188, P = 0.669); for body mass index in the ConG (2.2%, F = 0.046, P = 0.832) and DieG (2.3%, F = 0.098, P = 0.758.); and waist-to-hip ratio in the ConG (0%, F = 0.002, P = 0.968) and DieG (0%, F = 0.023, P = 0.882). However, clinically significant changes were observed in HbA1c in the ConG male group (23% decrease); percentage body fat for the ConG (16.7%, F = 1.682, P = 0.208, g = 0.534) and DieG (13.0%, F = 0.638, P = 0435, g = 0.361); for waist circumferences in the ConG (5.4%, F = 0.686, P = 0.416, g = 0.341) and DieG (6.3%, F = 1.327, P = 0.264, g = 0.520); and for hip circumference in the ConG (5.8%, F = 0.993, P = 0.329, g = 0.410) and DieG (7.0%, F = 2.668, P = 0.119, g = 0.737). Results indicate that moderate clinically significant changes in body composition are achievable with LCHFD and/or daily walking in obese adults living with T2D. However, more robust research is required to determine the effects of LCHFD, with or without concurrent physical activity, on obesity and other diabetic complication markers.

Greater Loss of Central Adiposity from Low-Carbohydrate versus Low-Fat Diet in Middle-Aged Adults with Overweight and Obesity.

The objective of this study is to determine whether middle-aged adults prescribed a low carbohydrate-high fat (LCHF) or low fat (LF) diet would have greater loss of central fat and to determine whether the insulin resistance (IR) affects intervention response. A total of 50 participants (52.3 ± 10.7 years old; 36.6 ± 7.4 kg/m2 BMI; 82% female) were prescribed either a LCHF diet (n = 32, carbohydrate: protein: fat of 5%:30%:65% without calorie restriction), or LF diet (n = 18, 63%:13–23%: 10–25% with calorie restriction of total energy expenditure—500 kcal) for 15 weeks. Central and regional body composition changes from dual-x-ray absorptiometry and serum measures were compared using paired t-tests and ANCOVA with paired contrasts. IR was defined as homeostatic model assessment (HOMA-IR) > 2.6. Compared to the LF group, the LCHF group lost more android (15.6 ± 11.2% vs. 8.3 ± 8.1%, p < 0.01) and visceral fat (18.5 ± 22.2% vs. 5.1 ± 15.8%, p < 0.05). Those with IR lost more android and visceral fat on the LCHF verses LF group (p < 0.05). Therefore, the clinical prescription to a LCHF diet may be an optimal strategy to reduce disease risk in middle-aged adults, particularly those with IR.

Immune Function Response Following a Low-carbohydrate, High-fat Diet (LCHFD) in Patients with Type 2 Diabetes

Background: Type 2 diabetes is a chronic metabolic disorder that can result in micro- and macrovascular complications and is complicated by an impaired healing process. Research suggests that both dietary factors and habitual physical activity influence the hemostatic system through several pathways. Objectives: The study attempted to investigate if a low-carbohydrate, high-fat diet (LCHFD), on its own or in conjunction with physical activity, could alter hematologic variables in patients with type 2 diabetes. Methods: Participants (n = 39; 31 - 71 y.) were assigned into three groups, which included either a 16 week continuous physical activity program with the consumption of an LCHFD (ExDG) (n = 13; 41 - 71 y), consuming only a LCHFD group (DietG) (n = 13; 31 - 71 y.), or a control group (ConG) (n = 13; 44 - 69 y). Participants in the ExDG were advised only to consume a diet high in fat and not consume more than 50 g of carbohydrates per day. Furthermore, participants had to walk a minimum of 10000 steps per day. The DietG were instructed to only consume a diet high in fat and low in carbohydrates, where the ConG continued with their normal daily routine. Results: No significant changes (P &gt; 0.05) were observed in white blood cell count, neutrophils, lymphocytes, eosinophils, basophils, hemoglobin, red blood cell count, mean corpuscular volume, hematocrit, mean corpuscular hemoglobin, platelets, red blood cell distribution width, mean corpuscular hemoglobin concentration, and C-reactive protein following ExDG, DietG or in the ConG. Conclusions: A LCHFD on its own or in conjunction with physical activity does not have any effect on the measured hematologic variables in patients with type 2 diabetes. This may be due to the current popular recommendation of LCHFD not being useful in type 2 diabetics and 10000 steps being of insufficient intensity to improve hematologic parameters in type 2 diabetics.

Low-Carbohydrate High-Fat Diet and Exercise: Effect of a 10-Week Intervention on Body Composition and CVD Risk Factors in Overweight and Obese Women-A Randomized Controlled Trial.

We assessed the effect of weight-loss induced with a low-carbohydrate-high-fat diet with and without exercise, on body-composition, cardiorespiratory fitness and cardiovascular risk factors. A total of 57 overweight and obese women (age 40 ± 3.5 years, body mass index 31.1 ± 2.6 kg∙m−2) completed a 10-week intervention using a low-carbohydrate-high-fat diet, with or without interval exercise. An equal deficit of 700 kcal∙day−1 was prescribed, restricting diet only, or moderately restricting diet and adding exercise, producing four groups; normal diet (NORM); low-carbohydrate-high-fat diet (LCHF); normal diet and exercise (NORM-EX); and low-carbohydrate-high-fat diet and exercise (LCHF-EX). Linear Mixed Models were used to assess between-group differences. The intervention resulted in an average 6.7 ± 2.5% weight-loss (p < 0.001). Post-intervention % fat was lower in NORM-EX than NORM (40.0 ± 4.2 vs. 43.5 ± 3.5%, p = 0.024). NORM-EX reached lower values in total cholesterol than NORM (3.9 ± 0.6 vs. 4.7 ± 0.7 mmol/L, p = 0.003), and LCHF-EX (3.9 ± 0.6 vs. 4.9 ± 1.1 mmol/L, p = 0.004). Post intervention triglycerides levels were lower in NORM-EX than NORM (0.87 ± 0.21 vs. 1.11 ± 0.34 mmol/L, p = 0.030). The low-carbohydrate-high-fat diet had no superior effect on body composition, O2peak or cardiovascular risk factors compared to a normal diet, with or without exercise. In conclusion, the intervention decreased fat mass, but exercise improved body composition and caused the most favorable changes in total cholesterol and triglycerides in the NORM-EX. Exercise increased cardiorespiratory fitness, regardless of diet.

Ketogenic Diet: A Dietary Modification as an Anxiolytic Approach?

Anxiety disorders comprise persistent, disabling conditions that are distributed across the globe, and are associated with the high medical and socioeconomic burden of the disease. Within the array of biopsychosocial treatment modalities—including monoaminergic antidepressants, benzodiazepines, and CBT—there is an unmet need for the effective treatment of anxiety disorders resulting in full remission and recovery. Nutritional intervention may be hypothesized as a promising treatment strategy; in particular, it facilitates relapse prevention. Low-carbohydrate high-fat diets (LCHF) may provide a rewarding outcome for some anxiety disorders; more research is needed before this regimen can be recommended to patients on a daily basis, but the evidence mentioned in this paper should encourage researchers and clinicians to consider LCHF as a piece of advice somewhere between psychotherapy and pharmacology, or as an add-on to those two.

Exploring the highs and lows of very low carbohydrate high fat diets on weight loss and diabetes‐ and cardiovascular disease‐related risk markers: A systematic review

AbstractAimVery low carbohydrate high fat diets (VLCHF) are increasingly popular for weight loss and diabetes management, but the risk implications of long‐term adherence to a high‐fat‐diet remain unclear, especially in high‐risk populations. This review aimed to examine adherence, weight loss, diabetes‐ and cardiovascular disease (CVD)‐related risk markers in adults consuming VLCHF diets.MethodsOnline databases were searched for randomised controlled trials ≥3 months duration that met a pre‐defined macronutrient prescription: VLCHF ≤25%E carbohydrate, &gt;35%E fat; low fat (LF) ≥45%E carbohydrate, ≤30%E fat; and reported energy, saturated fat (SFA), weight, blood glucose, cholesterol and blood pressure (BP). Studies were excluded if the macronutrient prescription was not targeted (n = 32); not met (n = 17) or not reported (n = 13).ResultsEight studies included: 1217 commenced; 922 completed overweight and obese adults. Diets were isocaloric moderately energy‐restricted, closely monitored with ongoing support from dietitians, physicians, and/or nurses. Four studies reported non‐adherence beyond 3 months (n = 3) and 6 months (n = 1) despite interventions of 12, 15 and 24 months. VLCHF diets were high in fat and SFA (fat 49%‐56%E; SFA 11%‐21%E) compared to LF diets (fat 13%‐29%E; SFA 5%‐11%E). All groups achieved significant weight loss and improvements in BP and blood glucose. LDL‐C reduction favoured LF, P &lt; .05; increased HDL‐C and reduced triglyceride levels favoured VLCHF, P &lt; .05.ConclusionsVLCHF and LF diets with moderate energy restriction demonstrate similar weight loss and improvements to BP to 3 months. However, adherence is likely poor without intensive support from health professionals. Dietary SFA should be monitored to ensure recommended intakes, but longer‐term studies with high adherence are required to confirm the level of CVD‐risk and potential harms.

Would creatine supplementation augment exercise performance during a low carbohydrate high fat diet?

Low carbohydrate high fat (LCHF) diets are emerging in popularity. Several athletics have adopted LCHF diets in an attempt to improve exercise performance and body composition by enhancing fat utilization. However, these diets impair maximal and supramaximal exercise performance due to limited glycogen stores as well as increasing ratings of perceived exertion (RPE). All of these factors may impact training volume and compliance, leading to less optimal training adaptations over time. In contrast, LCHF diets is an effective strategy for weight and fat mass loss and is beneficial for a variety of metabolic processes. One potential nutritional strategy to off-set the negative aspects of a LCHF is creatine (Cr). Creatine supplementation has been shown to increase muscle power output and reduce the rate of fatigue; thereby allowing individuals to work at a higher intensity for a greater duration. Furthermore, Cr supplementation may positively enhance body composition (gains in muscle mass and possibly aid in fat mass loss). Despite the popularity of both LCHF and creatine supplementation, there is no data available investigating the effects of Cr supplementation on exercise performance and body composition during LCHF diets in humans. We would hypothesize that Cr supplementation may augment exercise performance (anerobic power and strength) during a LCHF diet compared to a LCHF diet and placebo. In addition, combining Cr with a LCHF diet would further increase body fat loss and improve body composition compared to a LCHF diet and/or low-fat diets (LFDs) placebo. Our hypotheses would be under the assumption that total caloric intake and protein intake are matched. Future research is warranted to examine chronic exercise with LCHF diets with and without creatine and compare performance and body composition changes to high carbohydrate diets.

Acute Ketogenic Diet and Ketone Ester Supplementation Impairs Race Walk Performance.

This study aimed to determine if LCHF and ketone ester (KE) supplementation can synergistically alter exercise metabolism and improve performance. Elite race walkers (n = 18, 15 males and 3 females; V˙O2peak, 62 ± 6 mL·min-1·kg-1) undertook a four-stage exercise economy test and real-life 10,000-m race before and after a 5-d isoenergetic high-CHO (HCHO, ~60%-65% fat; CHO, 20% fat; n = 9) or LCHF (75%-80% fat, <50 g·d-1 CHO, n = 9) diet. The LCHF group performed additional economy tests before and after diet after supplementation with 573 mg·kg-1 body mass KE (HVMN; HVMN Inc., San Francisco, CA), which was also consumed for race 2. The oxygen cost of exercise (relative V˙O2, mL·min-1·kg-1) increased across all four stages after LCHF (P < 0.005). This occurred in association with increased fat oxidation rates, with a reciprocal decrease in CHO oxidation (P < 0.001). Substrate utilization in the HCHO group remained unaltered. The consumption of KE before the LCHF diet increased circulating KB (P < 0.05), peaking at 3.2 ± 0.6 mM, but did not alter V˙O2 or RER. LCHF diet elevated resting circulating KB (0.3 ± 0.1 vs 0.1 ± 0.1 mM), but concentrations after supplementation did not differ from the earlier ketone trial. Critically, race performance was impaired by ~6% (P < 0.0001) relative to baseline in the LCHF group but was unaltered in HCHO. Despite elevating endogenous KB production, an LCHF diet does not augment the metabolic responses to KE supplementation and negatively affects race performance.

Influence of a Low-Carbohydrate High-Fat Diet on Peritoneal Inflammation, Cancer-Associated Lymphocytes, and Survival in a Murine Carcinomatous Peritonitis Model.

Low-carbohydrate high-fat diets (LCHFDs) are thought to be beneficial for metabolic support in patients with advanced cancer. However, whether LCHFDs affect the progression of carcinomatous peritonitis (CP) remains unclear. Our study examined the influence of a lard-based LCHFD on host immunity and survival in a murine CP model. Mice were fed either a normal diet (ND) or an LCHFD ad libitum. On day 7, Panc02 cancer cells were inoculated intraperitoneally. Mice were killed on days 7, 21, and 35, and cytokine levels in the peritoneal fluid, as well as the number and phenotypes of peritoneal, splenic, and tumor-infiltrating lymphocytes were measured. Survival studies were performed with both ad libitum and isocaloric feeding in other sets of mice. The levels of all cytokines significantly increased in the LCHFD group compared with those in the ND group on day 21. The tumor necrosis factor α and interleukin-10 levels were higher in the LCHFD group than in the ND group on day 35. In the LCHFD group, the regulatory T-cell (Treg) number was significantly higher in the peritoneal cavity and tumor. The survival times were worse in the LCHFD group than in the ND group. The ad libitum, lard-based LCHFD feeding of CP mice increases the peritoneal cytokine levels, which may reduce splenic, anticancer lymphocytes and increase the number of Tregs in the peritoneal cavity and tumor. The detrimental effects of LCHFD are linked to dietary composition rather than overfeeding.

Comparison of Fasting With Low-carbohydrate High-fat Diet for the Standardized Uptake Values of ^(18)F-FDG in Human Tissues and Different Cancers

Comparison of Fasting With Low-carbohydrate High-fat Diet for the Standardized Uptake Values of ^(18)F-FDG in Human Tissues and Different Cancers

Adaptation to a low carbohydrate high fat diet is rapid but impairs endurance exercise metabolism and performance despite enhanced glycogen availability.

Key points Brief (5–6 days) adaptation to a low carbohydrate high fat diet in elite athletes increased exercise fat oxidation to rates previously observed with medium (3–4 weeks) or chronic (>12 months) adherence to this diet, with metabolic changes being washed out in a similar time frame.Increased fat utilisation during exercise was associated with a 5–8% increase in oxygen cost at speeds related to Olympic Programme races.Acute restoration of endogenous carbohydrate (CHO) availability (24 h high CHO diet, pre‐race CHO) only partially restored substrate utilisation during a race warm‐up. Fat oxidation continued to be elevated above baseline values although it was lower than achieved by 5–6 days’ keto adaptation; CHO oxidation only reached 61% and 78% of values previously seen at exercise intensities related to race events.Acute restoration of CHO availability failed to overturn the impairment of high‐intensity endurance performance previously associated with low carbohydrate high fat adaptation, potentially due to the blunted capacity for CHO oxidation. We investigated substrate utilisation during exercise after brief (5–6 days) adaptation to a ketogenic low‐carbohydrate (CHO), high‐fat (LCHF) diet and similar washout period. Thirteen world‐class male race walkers completed economy testing, 25 km training and a 10,000 m race (Baseline), with high CHO availability (HCHO), repeating this (Adaptation) after 5–6 days’ LCHF (n = 7; CHO: <50 g day−1, protein: 2.2 g kg−1 day−1; 80% fat) or HCHO (n = 6; CHO: 9.7 g kg−1 day−1; protein: 2.2 g kg−1 day−1) diet. An Adaptation race was undertaken after 24 h HCHO and pre‐race CHO (2 g kg−1) diet, identical to the Baseline race. Substantial (>200%) increases in exercise fat oxidation occurred in the LCHF Adaptation economy and 25 km tests, reaching mean rates of ∼1.43 g min−1. However, relative V˙O2 (ml min−1 kg−1) was higher (P < 0.0001), by ∼8% and 5% at speeds related to 50 km and 20 km events. During Adaptation race warm‐up in the LCHF group, rates of fat and CHO oxidation at these speeds were decreased and increased, respectively (P < 0.001), compared with the previous day, but were not restored to Baseline values. Performance changes differed between groups (P = 0.009), with all HCHO athletes improving in the Adaptation race (5.7 (5.6)%), while 6/7 LCHF athletes were slower (2.2 (3.4)%). Substrate utilisation returned to Baseline values after 5–6 days of HCHO diet. In summary, robust changes in exercise substrate use occurred in 5–6 days of extreme changes in CHO intake. However, adaptation to a LCHF diet plus acute restoration of endogenous CHO availability failed to restore high‐intensity endurance performance, with CHO oxidation rates remaining blunted.

Intramuscular Mechanisms Mediating Adaptation to Low-Carbohydrate, High-Fat Diets during Exercise Training.

Interest in low-carbohydrate, high-fat (LCHF) diets has increased over recent decades given the theorized benefit of associated intramuscular adaptations and shifts in fuel utilization on endurance exercise performance. Consuming a LCHF diet during exercise training increases the availability of fat (i.e., intramuscular triglyceride stores; plasma free fatty acids) and decreases muscle glycogen stores. These changes in substrate availability increase reliance on fat oxidation for energy production while simultaneously decreasing reliance on carbohydrate oxidation for fuel during submaximal exercise. LCHF diet-mediated changes in substrate oxidation remain even after endogenous or exogenous carbohydrate availability is increased, suggesting that the adaptive response driving changes in fat and carbohydrate oxidation lies within the muscle and persists even when the macronutrient content of the diet is altered. This narrative review explores the intramuscular adaptations underlying increases in fat oxidation and decreases in carbohydrate oxidation with LCHF feeding. The possible effects of LCHF diets on protein metabolism and post-exercise muscle remodeling are also considered.

High-fat versus high-carbohydrate diets for optimal higher intensity endurance exercise performance: and the winner is….

High-fat versus high-carbohydrate diets for optimal higher intensity endurance exercise performance: and the winner is….

A 3-Week, Low-Carbohydrate, High-Fat Diet Improves Multiple Serum Inflammatory Markers in Endurance-Trained Males.

Waldman, HS, Heatherly, AJ, Killen, LG, Hollingsworth, A, Koh, Y, and O'Neal, EK. A three-week, low-carbohydrate, high-fat diet improves multiple serum inflammatory markers in endurance-trained males. J Strength Cond Res 36(9): 2502-2508, 2022-This study examined the effects of a low-carbohydrate, high-fat diet (LCHF) on inflammatory marker responses in middle-aged endurance athletes. Eight male runners maintained their habitual mixed diet (HMD) in the first phase of the study before switching to a noncalorically restricted LCHF diet (∼70% of kcals from fat; carbohydrate <50 g) for 3 weeks. Subjects completed a 50-minute fixed pace treadmill running protocol in a hot environment, followed by a 5-km outdoor time trial. Fasting serum samples were collected immediately after exercise and heat stress restriction, and again 24 hours after the exercise/heat stressor. Thirty inflammation markers were assessed using the multiplex flow immunoassay technique. Seven markers (BAFF/TNFSF-13, sCD30/TNFRSF8, sCD163, Chitinase3-like1, gp130SIL-6Rβ, sTNFR-1, and sTNFR-2) reached statistical significance ( p < 0.05) favoring LCHF before exercise, and sCD30/TNFRSF8 favored ( p < 0.05) LCHF before (HMD = 459 ± 111; LCHF = 296 ± 100) and after (HMD = 385 ± 104; LCHF = 285 ± 104 pg·ml -1 ) exercise. Although the current dietary intervention was short in duration, LCHF seems to offer some protection against multiple chronic inflammation markers for physically active men between ages 30 and 50 years.

A moderate-carbohydrate diet with plant protein is inversely associated with cardiovascular risk factors: the Korea National Health and Nutrition Examination Survey 2013\u20132017

BackgroundBecause a moderate-carbohydrate diet reportedly has minimal risks, the substitution of carbohydrate for protein has been emphasized. Few studies have explored the effect of moderate-carbohydrate diets with higher protein intake in Asians, who typically consume a high-carbohydrate low-fat diet. Therefore, this study evaluated the associations of moderate- versus high- carbohydrate diets with cardiovascular risk factors among Korean adults by protein source.MethodsThis study included 7965 adults (3196 men, 4769 women) aged ≥ 19 years who participated in the 2013–2017 Korea National Health and Nutrition Examination Survey. Dietary intake was assessed by a 24-h recall method and four types of diet were defined: a moderate-carbohydrate diet with plant protein (MCP) or animal protein (MCA) and a high-carbohydrate diet with plant protein (HCP) or animal protein (HCA).ResultsCompared with the MCP group, men in the other three groups had significantly higher odds ratios (ORs) for elevated total cholesterol, reduced high-density lipoprotein (HDL)-cholesterol, and metabolic syndrome. Among women, only the HCP group had an increased OR for reduced HDL-cholesterol, compared with the MCP group. Similar associations were observed in younger adults (19–49 years). In addition, younger adults in the MCA group exhibited higher ORs for elevated triglycerides in men and elevated total cholesterol in women, compared with those in the MCP group.ConclusionsA moderate-carbohydrate diet with a high intake of plant protein was inversely associated with cardiovascular risk factors, especially among younger Korean adults. Further intervention studies are required to confirm this relationship and develop the optimal diet for cardiovascular health in the Korean population.