Ditta Valsdottir

• Clauss, Matthieu; Skattebo, Øyvind; Rasen Dæhli, Malin; Valsdottir, Thorhildur Ditta; Bastani, Nasser Ezzatkhah & Johansen, Egil Ivar [Show all 9 contributors for this article] (2023). Carbohydrate Ingestion during Prolonged Cycling Improves Next-Day Time Trial Performance and Alters Amino Acid Concentrations. Medicine & Science in Sports & Exercise. ISSN 0195-9131. 55(12), p. 2228–2240. doi: 10.1249/MSS.0000000000003264.
• Valsdottir, Thorhildur Ditta; Øvrebø, Bente; Kornfeldt, Thea Martine; Litleskare, Sigbjørn; Johansen, Egil Ivar & Henriksen, Christine [Show all 7 contributors for this article] (2023). Effect of aerobic exercise and low-carbohydrate high-fat diet on glucose tolerance and android/gynoid fat in overweight/obese women: A randomized controlled trial. Frontiers in Physiology. ISSN 1664-042X. 14. doi: 10.3389/fphys.2023.1056296. Full text in Research Archive Show summary

  The study was designed to compare the effects of weight loss induced by a low-carbohydrate-high-fat diet or a normal diet, with and without exercise, on glucose tolerance measured as area under the curve (AUC), and android (A) and gynoid (G) fat distribution. The study was registered at clinicaltrials.gov; NCT04100356. In total, 57 women classified as overweight or obese (age 40 ± 3.5 years, body mass index 31.1 ± 2.6 kg/m2) were randomly assigned and completed a 10-week intervention using a low-carbohydrate high-fat diet or a normal diet, with or without aerobic interval exercise. An equal deficit of 700 kcal/day was prescribed, either restricting the diet only, or moderately restricting diet and including three 50-min high-intensity bicycle sessions per week. There were thus four groups: normal diet (NORM); low-carbohydrate-high-fat diet (LCHF); normal diet with exercise (NORM-EX); and low-carbohydrate-high-fat diet with exercise (LCHF-EX). Linear mixed models was used to assess differences between groups. With all groups pooled, the intervention resulted in a weight loss of 6.7 ± 2.5% (p < 0.001). The intervention did not result in differences between groups in AUC glucose, nor in fasting glucose or indicis for insulin resistance such as Homeostatic Model Assessment, Matsuda Insulin Sensitivity Index, insulinogenic index and disposition index. Post-intervention android fat was lower in LCHF than NORM (3,223 ± 727 vs. 2,533 ± 535 g, p = 0.041). LCHF reached a lower A/G ratio than NORM (0.94 ± 0.12 vs. 1.04 ± 0.09, p = 0.011) and LCHF-EX (0.94 ± 0.12 vs. 1.09 ± 0.09, p < 0.001) after the intervention. LCHF resulted in lower android fat mass compared to NORM and the lowest A/G ratio compared to the other matched groups, but with no accompanying improvement in AUC glucose. In conclusion, although all groups achieved improvements in glucose tolerance, no superior effect was observed with the LCHF diet, neither with nor without exercise.

• Valsdottir, Thorhildur Ditta; Øvrebø, Bente; Falck, Thea Martine; Litleskare, Sigbjørn; Johansen, Egil Ivar & Henriksen, Christine [Show all 7 contributors for this article] (2020). 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. Nutrients. ISSN 2072-6643. 13(1). doi: 10.3390/nu13010110. Full text in Research Archive Show summary

  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, V˙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.

• Valsdottir, Thorhildur; Henriksen, Christine; Odden, Nancy; Nellemann, Birgitte; Jeppesen, Per B & Hisdal, Jonny [Show all 8 contributors for this article] (2019). Effect of a Low-Carbohydrate High-Fat Diet and a Single Bout of Exercise on Glucose Tolerance, Lipid Profile and Endothelial Function in Normal Weight Young Healthy Females. Frontiers in Physiology. ISSN 1664-042X. 10, p. 1–15. doi: 10.3389/fphys.2019.01499. Full text in Research Archive
• Jelstad, Stian S.; Valsdottir, Thorhildur; Johansen, Egil Ivar & Jensen, Jørgen (2019). Eight sessions of endurance training decrease fasting glucose and improve glucose tolerance in middle-aged overweight males. Archives of Physiology and Biochemistry. ISSN 1381-3455. 127(1), p. 12–19. doi: 10.1080/13813455.2018.1563189. Full text in Research Archive Show summary

  Exercise improves metabolic regulation and reduces the risk of developing type 2 diabetes and other metabolic diseases. The recommendations for exercise are rather general and the health benefits of controlled training studies are important to make better recommendations. In the present study, we report that eight endurance training sessions over 3 weeks reduced fasting glucose, and improved glucose tolerance and plasma lipids in sedentary middle-aged males (44–64 years) with overweight or obesity (BMI: 27–38). The decrease in fasting glucose was substantial (from 5.3 ± 0.3 to 4.8 ± 0.2 mM; p < .001). The training sessions consisted of 60-min indoor-cycling at ∼83% of peak heart rate divided in four blocks of 15 min cycling, with 2-min rest between blocks. Maximal oxygen uptake did not increase (38.8 ± 1.8 vs. 39.0 ± 1.6 ml kg−1 min−1). In conclusion, 3-weekly sessions of moderate-/high-intensity endurance training can be recommended for untrained males with overweight or obesity to improve glucose homeostasis.

• Sollie, Ove; Jeppesen, Per Bendix; Tangen, Daniel S.; Jernerén, Fredrik; Nellemann, Birgitte & Valsdottir, Thorhildur [Show all 12 contributors for this article] (2018). Protein intake in the early recovery period after exhaustive exercise improves performance the following day. Journal of applied physiology. ISSN 8750-7587. 125(6), p. 1731–1742. doi: 10.1152/japplphysiol.01132.2017. Full text in Research Archive Show summary

  The aim of the present study was to investigate the effect of protein and carbohydrate ingestion during early recovery from exhaustive exercise on performance after 18-h recovery. Eight elite cyclists (V̇o2max: 74.0 ± 1.6 ml·kg−1·min−1) completed two exercise and diet interventions in a double-blinded, randomized, crossover design. Participants cycled first at 73% of V̇o2max (W73%) followed by 1-min intervals at 90% of V̇o2max until exhaustion. During the first 2 h of recovery, participants ingested either 1.2 g carbohydrate·kg−1·h−1 (CHO) or 0.8 g carbohydrate + 0.4 g protein·kg−1·h−1 (CHO + PROT). The diet during the remaining recovery period was similar for both interventions and adjusted to body weight. After an 18-h recovery, cycling performance was assessed with a 10-s sprint test, 30 min of cycling at W73%, and a cycling time trial (TT). The TT was 8.5% faster (41:53 ± 1:51 vs. 45:26 ± 1:32 min; P < 0.03) after CHO + PROT compared with CHO. Mean power output during the sprints was 3.7% higher in CHO + PROT compared with CHO (1,063 ± 54 vs. 1,026 ± 53 W; P = 0.01). Nitrogen balance in the recovery period was negative in CHO and neutral in CHO + PROT (−82.4 ± 11.5 vs. 7.0 ± 15.4 mg/kg; P < 0.01). In conclusion, TT and sprint performances were improved 18 h after exhaustive cycling by CHO + PROT supplementation during the first 2 h of recovery compared with isoenergetic CHO supplementation. Our results indicate that intake of carbohydrate plus protein after exhaustive endurance exercise more rapidly converts the body from a catabolic to an anabolic state than carbohydrate alone, thus speeding recovery and improving subsequent cycling performance.

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