Articles** relevant to fitness:
Training with a mean intensity of 60% of one repetition maximum elicits maximal gains in untrained individuals, whereas 80% is most effective in those who are trained. Untrained participants experience maximal gains by training each muscle group 3 d.wk and trained individuals 2 d.wk. Four sets per muscle group elicited maximal gains in both trained and untrained individuals.
Effect size data demonstrate that maximal strength gains are elicited among athletes who train at a mean training intensity of 85% of 1 repetition maximum (1RM), 2 days per week, and with a mean training volume of 8 sets per muscle group.
A greater proportion of the low-carbohydrate diet group than the low-fat diet group completed the study (76% vs. 57%; P = 0.02). At 24 weeks, weight loss was greater in the low-carbohydrate diet group than in the low-fat diet group (mean change, -12.9% vs. -6.7%; P < 0.001). Patients in both groups lost substantially more fat mass (change, -9.4 kg with the low-carbohydrate diet vs. -4.8 kg with the low-fat diet) than fat-free mass (change, -3.3 kg vs. -2.4 kg, respectively). Compared with recipients of the low-fat diet, recipients of the low-carbohydrate diet had greater decreases in serum triglyceride levels (change, -0.84 mmol/L vs. -0.31 mmol/L [-74.2 mg/dL vs. -27.9 mg/dL]; P = 0.004) and greater increases in high-density lipoprotein cholesterol levels (0.14 mmol/L vs. -0.04 mmol/L [5.5 mg/dL vs. -1.6 mg/dL]; P < 0.001).
By 1 year, mean (+/-SD) weight change for persons on the low-carbohydrate diet was -5.1 +/- 8.7 kg compared with -3.1 +/- 8.4 kg for persons on the conventional diet. Differences between groups were not significant (-1.9 kg [95% CI, -4.9 to 1.0 kg]; P = 0.20). For persons on the low-carbohydrate diet, triglyceride levels decreased more (P = 0.044) and high-density lipoprotein cholesterol levels decreased less (P = 0.025). As seen in the small group of persons with diabetes (n = 54) and after adjustment for covariates, hemoglobin A1c levels improved more for persons on the low-carbohydrate diet. These more favorable metabolic responses to a low-carbohydrate diet remained significant after adjustment for weight loss differences.
There is convincing evidence that a higher protein intake increases thermogenesis and satiety compared to diets of lower protein content. The weight of evidence also suggests that high protein meals lead to a reduced subsequent energy intake. Some evidence suggests that diets higher in protein result in an increased weight loss and fat loss as compared to diets lower in protein, but findings have not been consistent.
The low-carbohydrate group lost more weight (9.79 +/- 0.71 vs. 6.14 +/- 0.91 kg; P < 0.05) and more body fat (6.20 +/- 0.67 vs. 3.23 +/- 0.67 kg; P < 0.05) than the low-fat group. There were no differences in energy intake between the diet groups as reported on 3-d food records at the conclusion of the study (1422 +/- 73 vs. 1530 +/- 102 kcal; 5954 +/- 306 vs. 6406 +/- 427 kJ).
5) Foster GD, Wyatt HR, Hill JO, McGuckin BG, Brill C, Mohammed BS, Szapary PO, Rader DJ, Edman JS, Klein S. A randomized trial of a low-carbohydrate diet for obesity. N Engl J Med. 2003 May 22;348(21):2082-90.
RESULTS: Subjects on the low-carbohydrate diet had lost more weight than subjects on the conventional diet at 3 months (mean [+/-SD], -6.8+/-5.0 vs. -2.7+/-3.7 percent of body weight; P=0.001) and 6 months (-7.0+/-6.5 vs. -3.2+/-5.6 percent of body weight, P=0.02), but the difference at 12 months was not significant (-4.4+/-6.7 vs. -2.5+/-6.3 percent of body weight, P=0.26).
6) Fine EJ, Feinman RD. Thermodynamics of weight loss diets. Nutr Metab (Lond). 2004 Dec 8;1(1):15.
BACKGROUND: It is commonly held that "a calorie is a calorie", i.e. that diets of equal caloric content will result in identical weight change independent of macronutrient composition, and appeal is frequently made to the laws of thermodynamics. We have previously shown that thermodynamics does not support such a view and that diets of different macronutrient content may be expected to induce different changes in body mass. Low carbohydrate diets in particular have claimed a "metabolic advantage" meaning more weight loss than in isocaloric diets of higher carbohydrate content. In this review, for pedagogic clarity, we reframe the theoretical discussion to directly link thermodynamic inefficiency to weight change. The problem in outline: Is metabolic advantage theoretically possible? If so, what biochemical mechanisms might plausibly explain it? Finally, what experimental evidence exists to determine whether it does or does not occur? RESULTS: Reduced thermodynamic efficiency will result in increased weight loss. The laws of thermodynamics are silent on the existence of variable thermodynamic efficiency in metabolic processes. Therefore such variability is permitted and can be related to differences in weight lost. The existence of variable efficiency and metabolic advantage is therefore an empiric question rather than a theoretical one, confirmed by many experimental isocaloric studies, pending a properly performed meta-analysis.
7) Komatsu T, Nakamori M, Komatsu K, Hosoda K, Okamura M, Toyama K, Ishikura Y, Sakai T, Kunii D, Yamamoto S. Oolong tea increases energy metabolism in Japanese females. J Med Invest. 2003 Aug;50(3-4):170-5.
The cumulative increases of EE for 120 min were significantly increased 10% and 4% after the consumption of oolong tea and green tea, respectively. EE at 60 and 90 min were significantly higher after the consumption of oolong tea than that of water (P<0.05). In comparison with green tea, oolong tea contained approximately half the caffeine and epigallocatechin galate, while polymerized polyphenols were double. These results suggest that oolong tea increases EE by its polymerized polyphenols.
8) Choo JJ. Green tea reduces body fat accretion caused by high-fat diet in rats through beta-adrenoceptor activation of thermogenesis in brown adipose tissue. J Nutr Biochem. 2003 Nov;14(11):671-6.
The simultaneous administration of the beta-adrenoceptor antagonist propranolol(500 mg/kg diet) inhibited the body fat-suppressive effect of green tea extract. Propranolol also prevented the increase in protein content of interscapular brown adipose tissue caused by green tea extract. Digestibility was slightly reduced by green tea extract and this effect was not affected by propranolol. Therefore it appeared that green tea exerts potent body fat-suppressive effects in rats fed on a high-fat diet and the effect was resulted in part from reduction in digestibility and to much greater extent from increase in brown adipose tissue thermogenesis through beta-adrenoceptor activation.
9) Baird IM, Shephard NW, Merritt RJ, Hildick-Smith G. Repeated dose study of sucralose tolerance in human subjects. Food Chem Toxicol. 2000;38 Suppl 2:S123-9.
Sucralose dosage levels were 125mg/day for weeks 1-3, 250mg/day during weeks 4-7, and 500mg/day during weeks 8-12. No adverse experiences or clinically detectable effects were attributable to sucralose in either study. Similarly, haematology, serum biochemistry, urinalysis and EKG tracings were unaffected by sucralose administration. In the 13-week study, serial slit lamp ophthalmologic examination performed in a random subset of the study groups revealed no changes. Fasting and 2-hour post-dosing blood sucralose concentrations obtained daily during week 12 of the study revealed no rising trend for blood sucralose. Sucralose was well tolerated by human volunteers in single doses up to 10mg/kg/day and repeated doses increasing to 5mg/kg/day for 13 weeks.
One of the 7-day periods served as a control condition, where a placebo beverage was consumed following the exercise bouts on days 1, 3, 4, and 6 (CON). During the other 7-day protocol (POST), participants consumed a predefined formula beverage with added carbohydrate following the exercise bouts on days 1, 3, 4, and 6. Energy intake and macronutrient proportions were the same between the 2 trials; the only difference was the timing at which the macronutrients were consumed. Calculated fat oxidation was greater during exercise on day 6 during POST as compared to CON (p < .05).
11) Taheri S, Lin L, Austin D, Young T, Mignot E. Short Sleep Duration Is Associated with Reduced Leptin, Elevated Ghrelin, and Increased Body Mass Index. PLoS Med. 2004 Dec;1(3):e62. Epub 2004 Dec 7.
A U-shaped curvilinear association between sleep duration and BMI was observed. In persons sleeping less than 8 h (74.4% of the sample), increased BMI was proportional to decreased sleep. Short sleep was associated with low leptin (p for slope = 0.01), with a predicted 15.5% lower leptin for habitual sleep of 5 h versus 8 h, and high ghrelin (p for slope = 0.008), with a predicted 14.9% higher ghrelin for nocturnal (polysomnographic) sleep of 5 h versus 8 h, independent of BMI. CONCLUSION: Participants with short sleep had reduced leptin and elevated ghrelin. These differences in leptin and ghrelin are likely to increase appetite, possibly explaining the increased BMI observed with short sleep duration.
Both weight loss and fat-free mass loss were greater with the AM than the PM meal pattern: 3.90 +/- 0.19 vs. 3.27 +/- 0.26 kg/6 wk, P < 0.05, and 1.28 +/- 0.14 vs. 0.25 +/- 0.16 kg/6 wk, P < 0.001, respectively. Change in fat mass and loss of body energy were affected by order of meal pattern ingestion. The PM pattern resulted in greater loss of fat mass in period 1 (P < 0.01) but not in period 2. Likewise, resting mid-afternoon fat oxidation rate was higher with the PM pattern in period 1 (P < 0.05) but not in period 2, corresponding with the fat mass changes. To conclude, ingestion of larger AM meals resulted in slightly greater weight loss, but ingestion of larger PM meals resulted in better maintenance of fat-free mass. Thus, incorporation of larger PM meals in a weight loss regimen may be important in minimizing the loss of fat-free mass.
13) Kern PA, Ong JM, Saffari B, Carty J. The effects of weight loss on the activity and expression of adipose-tissue lipoprotein lipase in very obese humans. N Engl J Med. 1990 Apr 12;322(15):1053-9.
There was a strongly positive correlation between the initial body-mass index and the magnitude of the increase in lipoprotein lipase activity (r = 0.80, P less than 0.01) and immunoreactive protein (r = 0.92, P less than 0.01). We conclude that weight loss in very obese subjects leads to the increased activity and expression of lipoprotein lipase, thereby potentially enhancing lipid storage and making further weight loss more difficult.
14) Yost TJ, Jensen DR, Haugen BR, Eckel RH. Effect of dietary macronutrient composition on tissue-specific lipoprotein lipase activity and insulin action in normal-weight subjects. Am J Clin Nutr. 1998 Aug;68(2):296-302.
In summary, 16 d of HC compared with HF feeding in normal-weight subjects increased the responsiveness of ATLPL to an HC compared with an HF meal. However, the same diets had no effect on fasting ATLPL or SMLPL, the responsiveness of SMLPL to a meal, or S(I). These data suggest that in normal-weight subjects habitual dietary carbohydrate intake may have a stronger effect on subcutaneous fat storage than does dietary fat intake.
1) Touyz RM, Campbell N, Logan A, Gledhill N, Petrella R, Padwal R; Canadian Hypertension Education Program. The 2004 Canadian recommendations for the management of hypertension: Part III--Lifestyle modifications to prevent and control hypertension. Can J Cardiol. 2004 Jan;20(1):55-9.
RECOMMENDATIONS: Key recommendations include the following: lifestyle modification should be extended to nonhypertensive individuals who are at risk for developing high blood pressure; 30 min to 45 min of aerobic exercise should be performed on most days (four to five days) of the week; an ideal body weight (body mass index 18.5 kg/m2 to 24.9 kg/m2) should be maintained and weight loss strategies should use a multidisciplinary approach; alcohol consumption should be limited to two drinks or fewer per day, and weekly intake should not exceed 14 standard drinks for men and nine standard drinks for women ...a diet that emphasizes fruits, vegetables ... and maintains an adequate intake of potassium, magnesium and calcium, should be followed; salt intake should be restricted to 65 mmol/day to 100 mmol/day in hypertensive individuals and less than 100 mmol/day in normotensive individuals at high risk for developing hypertension; and stress management should be considered as an intervention in selected individuals.
2) Liu L, Ikeda K, Sullivan DH, Ling W, Yamori Y. Epidemiological evidence of the association between dietary protein intake and blood pressure: a meta-analysis of published data. Hypertens Res. 2002 Sep;25(5):689-95.
Results from two longitudinal studies showed inverse associations between dietary protein intake and BP after 3 and 7 years' follow-up. In conclusion, a convincing cross-sectional inverse association between dietary protein intake and BP was demonstrated by the meta-analysis of nine population-based studies.
3) Geleijnse JM, Giltay EJ,
RESULTS : Intake of fish oil was high in most trials (median dose: 3.7 g/day). Fish oil reduced systolic BP by 2.1 mmHg [95% confidence interval (CI): 1.0, 3.2; P < 0.01] and diastolic BP by 1.6 mmHg (95% CI: 1.0. 2.2; P < 0.01). Restricting the analysis to double-blind trials yielded BP reductions of 1.7 mmHg (95% CI: 0.3, 3.1) and 1.5 mmHg (95% CI: 0.6, 2.3), respectively. BP effects tended to be larger in populations that were older (> 45 years) and in hypertensive populations (BP >or= 140/90 mmHg). CONCLUSIONS : High intake of fish oil may lower BP, especially in older and hypertensive subjects. The antihypertensive effect of lower doses of fish oil (< 0.5 g/day) however, remains to be established.
4) Li D. Omega-3 fatty acids and non-communicable diseases. Chin Med J (Engl). 2003 Mar;116(3):453-8.
RESULTS: omega-3 PUFA has beneficial effects on increasing heart rate variability, decreasing the risk of stroke, reducing both systolic and diastolic blood pressure, insulin resistance and glucose metabolism. Long chain omega-3 PUFA has anti-cancer and anti-inflammatory activities. omega-3 PUFA has also been reported to have a beneficial effect on attention-deficit/hyperactivity disorder and schizophrenia, and may be effective in managing depression in adults.
5) Rupp H, Wagner D, Rupp T, Schulte LM, Maisch B. Risk Stratification by the "EPA+DHA Level" and the "EPA/AA Ratio"Focus on Anti-Inflammatory and Antiarrhythmogenic Effects of Long-Chain Omega-3 Fatty Acids. Herz. 2004 Nov;29(7):673-685.
Evidence is summarized strengthening the concept that a low "EPA+DHA level" presents a risk for sudden cardiac death and that the administration of 840 mg/day of EPA+DHA ethyl esters raises the "EPA+DHA level" to approximately 6% that is associated with a marked protection from sudden cardiac death. For reducing pro-inflammatory eicosanoids and cytokines, a higher "EPA+DHA level" is required which can be achieved with an intake of 2-4 g/day of 84% EPA+DHA ethyl esters. For assessing influences from pro-inflammatory eicosanoids and cytokines, the EPA/arachidonic acid ratio ("EPA/AA ratio") was identified as diagnostic parameter. To assess the dietary EPA+DHA intake, fatty acids were determined in fish dishes of the cafeteria of the Philipps University Hospital Marburg, Germany. The EPA+DHA content of the popular Alaska Pollock was 125 +/- 70 mg/100 g. A once daily fish dish can thus not provide the 840 mg/day EPA+DHA administered in the GISSI Prevention Study in the form of ethyl ester which markedly reduced the risk of sudden cardiac death in postmyocardial infarction patients. Nonetheless, at least two preferably oily fish meals per week should be consumed as preventive measure by persons without coronary artery disease. With documented coronary heart disease, it was advised to consume approximately 1 g/day of EPA+DHA.
6) Arntz HR. [Recommendations for secondary prevention after myocardial infarction] Z Kardiol. 2004;93 Suppl 1:I23-5. [Article in German]
The new ESC guidelines for secondary prevention after STEMI recommend acetylsalicylic acid, betablockers, ACE inhibitors, statins and as a new therapeutic option 1 g n-3-fatty acids. They also advocate strict control of elevated blood pressure and plasma glucose level. To stop smoking remains obligatory, supplemented by the advice to adhere to a mediterranean diet. The clinical value of using 1 g n-3-fatty acids was shown in the GISSI-P trial and seem to reduce especially arrhythmic events. Considering the number needed to treat for the different pharmacologic therapies, betablockers and ACE inhibitors are essentials if not contraindicated, n-3-fatty acids and statins show each comparable efficacy while acetylsalicylic acid still provides a good cost/benefit relation due to its low price.
7) de Lorgeril M, Salen P. Suitability of the Mediterranean-style diet in the modern world.
... a striking protective effect of an alpha-linolenic acid (
8) Trumbo PR. The level of evidence for permitting a qualified health claim: FDA's review of the evidence for selenium and cancer and vitamin E and heart disease. J Nutr. 2005 Feb;135(2):354-6.
The evidence for a relationship between vitamin E and heart disease and selenium and cancer was reviewed by the U.S. FDA. It was determined that there was insufficient evidence to permit a qualified health claim for vitamin E and cancer [typo?; "heart disease"], whereas there was some evidence for permitting a qualified health claim for selenium and cancer.
9) Gottlieb DJ,
RESULTS: The median sleep time was 7 hours per night, with 27.1% of subjects sleeping 6 hours or less per night. Compared with those sleeping 7 to 8 hours per night, subjects sleeping 5 hours or less and 6 hours per night had adjusted odds ratios for DM of 2.51 (95% confidence interval, 1.57-4.02) and 1.66 (95% confidence interval, 1.15-2.39), respectively. Adjusted odds ratios for IGT were 1.33 (95% confidence interval, 0.83-2.15) and 1.58 (95% confidence interval, 1.15-2.18), respectively. Subjects sleeping 9 hours or more per night also had increased odds ratios for DM and IGT. These associations persisted when subjects with insomnia symptoms were excluded. CONCLUSIONS: A sleep duration of 6 hours or less or 9 hours or more is associated with increased prevalence of DM and IGT. Because this effect was present in subjects without insomnia, voluntary sleep restriction may contribute to the large public health burden of DM.
10) Spiegel K, Leproult R, L'hermite-Baleriaux M, Copinschi G, Penev PD, Van Cauter E. Leptin levels are dependent on sleep duration: relationships with sympathovagal balance, carbohydrate regulation, cortisol, and thyrotropin. J Clin Endocrinol Metab. 2004 Nov;89(11):5762-71.
Twenty-four-hour hormonal and glucose profiles were sampled at frequent intervals, and sympathovagal balance was estimated from heart rate variability in 11 subjects studied after 6 d of 4-h bedtimes (mean +/- sem of sleep duration during last 2 d: 3 h and 49 +/- 2 min) and after 6 d of 12-h bedtimes (sleep: 9 h and 03 +/- 15 min). A study with 8-h bedtimes was performed 1 yr later (sleep: 6 h and 52 +/- 10 min). Caloric intake and activity levels were carefully controlled in all studies. Mean levels, maximal levels, and rhythm amplitude of leptin were decreased (-19%, -26%, and -20%, respectively) during sleep restriction compared with sleep extension.
Overall reaction times of a central task were fastest after the BAL[1:1] meal concomitant to the highest overall tyrosine (Tyr) to LNAA ratio. Our findings suggest that the carbohydrate to protein ratio in food specifically influences higher cognitive functions in the morning. Except for a transient positive effect of rising blood glucose after a carbohydrate-rich meal, a protein-rich or balanced meal seems to result in better overall cognitive performance presumably because of less variation in glucose metabolism and/or higher modulation in LNAA ratios indicated by the overall GIR.
12) Verger P, Lagarde D, Batejat D, Maitre JF. Influence of the composition of a meal taken after physical exercise on mood, vigilance, performance. Physiol Behav. 1998 Jun 1;64(3):317-22.
The results show no difference in memory performance between exercise and rest conditions, nor between "protein" and "no protein" meal groups. They do show, however, that subjects feel happier after a meal with protein than after a meal without protein. The effects of the "no protein" meal on drowsiness differ with the glucide content of the meal. Subjects are less drowsy when they eat between 125 and 150 g of glucide than when they eat more than 150 g. The rousing effect induced by physical exercise is counterbalanced when subjects eat more than 150 g of carbohydrate.
13) Spring B, Chiodo J, Harden M, Bourgeois MJ, Mason JD, Lutherer L. Psychobiological effects of carbohydrates. J Clin Psychiatry. 1989 May;50 Suppl:27-33; discussion 34.
Only the carbohydrate meal significantly increased fatigue, which could not be attributed to hypoglycemia because plasma glucose remained elevated. Fatigue began approximately, when the carbohydrate meal elevated the plasma tryptophan ratio but ended even though the ratio remained elevated. Fatigue after a high-carbohydrate lunch could not be explained by reactive hypoglycemia or sweet taste, and could partially be explained by the hypothesis that fatigue parallels an elevation of the tryptophan ratio.