Kristine L. Clark

Appropriate Intervention Strategies for Weight Loss and Prevention of Weight Regain for Adults

In excess of 55% of adults in the United States are classified as either overweight (body mass index = 25-29.9 kg.m(-2)) or obese (body mass index > or = 30 kg.m(-2)). To address this significant public health problem, the American College of Sports Medicine recommends that the combination of reductions in energy intake and increases in energy expenditure, through structured exercise and other forms of physical activity, be a component of weight loss intervention programs. An energy deficit of 500-1000 kcal.d-1 achieved through reductions in total energy intake is recommended. Moreover, it appears that reducing dietary fat intake to <30% of total energy intake may facilitate weight loss by reducing total energy intake. Although there may be advantages to modifying protein and carbohydrate intake, the optimal doses of these macronutritents for weight loss have not been determined. Significant health benefits can be recognized with participation in a minimum of 150 min (2.5 h) of moderate intensity exercise per week, and overweight and obese adults should progressively increase to this initial exercise goal. However, there may be advantages to progressively increasing exercise to 200-300 min (3.3-5 h) of exercise per week, as recent scientific evidence indicates that this level of exercise facilitates the long-term maintenance of weight loss. The addition of resistance exercise to a weight loss intervention will increase strength and function but may not attenuate the loss of fat-free mass typically observed with reductions in total energy intake and loss of body weight. When medically indicated, pharmacotherapy may be used for weight loss, but pharmacotherapy appears to be most effective when used in combination with modifications of both eating and exercise behaviors. The American College of Sports Medicine recommends that the strategies outlined in this position paper be incorporated into interventions targeting weight loss and the prevention of weight regain for adults.

Creatine Supplementation Enhances Muscular Performance During High-Intensity Resistance Exercise

OBJECTIVE This study was undertaken to investigate the influence of oral supplementation with creatine monohydrate on muscular performance during repeated sets of high-intensity resistance exercise. SUBJECTS/DESIGN Fourteen active men were randomly assigned in a double-blind fashion to either a creatine group (n = 7) or a placebo group (n = 7). Both groups performed a bench press exercise protocol (5 sets to failure using each subjects predetermined 10-repetition maximum) and a jump squat exercise protocol (5 sets of 10 repetitions using 30% of each subjects 1-repetition maximum squat) on three different occasions (T1, T2, and T3) separated by 6 days. INTERVENTION Before T1, both groups received no supplementation. From T1 to T2, both groups ingested placebo capsules. From T2 to T3, the creatine group ingested 25 g creatine monohydrate per day, and the placebo group ingested an equivalent amount of placebo. MAIN OUTCOME MEASURES Total repetitions for each set of bench presses and peak power output for each set of jump squats were determined. Other measures included assessment of diet, body mass, skinfold thickness, and preexercise and 5-minute postexercise lactate concentrations. RESULTS Lifting performance was not altered for either exercise protocol after ingestion of the placebos. Creatine supplementation resulted in a significant improvement in peak power output during all 5 sets of jump squats and a significant improvement in repetitions during all 5 sets of bench presses. After creatine supplementation, postexercise lactate concentrations were significantly higher after the bench press but not the jump squat. A significant increase in body mass of 1.4 kg (range = 0.0 to 2.7 kg) was observed after creatine ingestion. CONCLUSION One week of creatine supplementation (25 g/day) enhances muscular performance during repeated sets of bench press and jump squat exercise.

Influence of exercise training on physiological and performance changes with weight loss in men.

PURPOSE The purpose of this study was to examine the physiological effects of a weight-loss dietary regimen with or without exercise. METHODS Thirty-five overweight men were matched and randomly placed into either a control group (C; N = 6) or one of three dietary groups; a diet-only group (D; N = 8), a diet group that performed aerobic exercise three times per week (DE; N = 11); and a diet group that performed both aerobic and strength training three times per week (DES; N = 10). RESULTS After 12 wk, D, DE, and DES demonstrated a similar and significant (P < or = 0.05) reduction in body mass (-9.64, -8.99, and -9.90 kg, respectively) with fat mass comprising 69, 78, and 97% of the total loss in body mass, respectively. The diet-only group also demonstrated a significant reduction in fat-free mass. Maximum strength, as determined by 1-RM testing in the bench press and squat exercise was significantly increased for DES in both the bench press (+19.6%) and squat exercise (+32.6%). Absolute peak O2 consumption was significantly elevated in DE (+24.8%) and DES (+15.4%). There were no differences in performance during a 30-s Wingate test for the DE and DES, whereas D demonstrated a significant decline in peak and mean power output. Resting metabolic rate (RMR) (kcal x d(-1)) was not significantly different for any of the groups except for the DE group. There were no significant changes in basal concentrations of serum glucose, BUN, cortisol, testosterone, and high density lipoprotein (HDL) cholesterol for any of the groups. Serum total cholesterol and low density lipoprotein (LDL) cholesterol were significantly decreased for all dietary groups. Serum triglycerides were significantly reduced for D and DES at week 6 and remained lower at week 12 for D, while triglycerides returned to baseline values for DES. CONCLUSIONS These data indicate that a weight-loss dietary regimen in conjunction with aerobic and resistance exercise prevents the normal decline in fat-free mass and muscular power and augments body composition, maximal strength, and maximum oxygen consumption compared with weight-loss induced by diet alone.

24-Week study on the use of collagen hydrolysate as a dietary supplement in athletes with activity-related joint pain.

ABSTRACT Background: Collagen hydrolysate is a nutritional supplement that has been shown to exert an anabolic effect on cartilage tissue. Its administration appears beneficial in patients with osteoarthritis. Objective: To investigate the effect of collagen hydrolysate on activity-related joint pain in athletes who are physically active and have no evidence of joint disease. Design and setting: A prospective, randomized, placebo-controlled, double-blind study was conducted at Penn State University in University Park, Pennsylvania. Parameters including joint pain, mobility, and inflammation were evaluated with the use of a visual analogue scale during a 24-week study phase. Study participants: Between September 2005 and June 2006, 147 subjects who competed on a varsity team or a club sport were recruited. Data from 97 of 147 subjects could be statistically evaluated. Intervention: One hundred and forty-seven subjects (72 male, 75 female) were randomly assigned to two groups: a group (n = 73) receiving 25 mL of a liquid formulation that contained 10 g of collagen hydrolysate (CH-Alpha)* and a group (n = 74) receiving a placebo, which consisted of 25 mL of liquid that contained xanthan. Main outcome measures: The primary efficacy parameter was the change in the visual analogue scales from baseline during the study phase in relation to the parameters referring to pain, mobility, and inflammation. Results: When data from all subjects (n = 97) were evaluated, six parameters showed statistically significant changes with the dietary supplement collagen hydrolysate (CH) compared with placebo: joint pain at rest, assessed by the physician (CH vs. placebo (–1.37 ± 1.78 vs. –0.90 ± 1.74 ( p = 0.025)) and five parameters assessed by study participants: joint pain when walking (–1.11 ± 1.98 vs. –0.46 ± 1.63, p = 0.007), joint pain when standing (–0.97 ± 1.92 vs. –0.43 ± 1.74, p = 0.011), joint pain at rest (–0.81 ± 1.77 vs. –0.39 ± 1.56, p = 0.039), joint pain when carrying objects (–1.45 ± 2.11 vs. –0.83 ± 1.71, p = 0.014) and joint pain when lifting (–1.79 ± 2.11 vs. –1.26 ± 2.09, p = 0.018). When a subgroup analysis of subjects with knee arthralgia (n = 63) was performed, the difference between the effect of collagen hydrolysate vs. placebo was more pronounced. The parameter joint pain at rest, assessed by the physician, had a statistical significance level of p = 0.001 (–1.67 ± 1.89 vs. –0.86 ± 1.77), while the other five parameters based on the participants’ assessments were also statistically significant: joint pain when walking ( p = 0.003 (– 1.38 ± 2.12 vs. – 0.54 ± 1.65)), joint pain when standing ( p = 0.015 (–1.17 ± 2.06 vs. –0.50 ± 1.68)), joint pain at rest with ( p = 0.021 (–1.01 ±1.92 vs. –0.47 ± 1.63)), joint pain when running a straight line ( p = 0.027 (–1.50 ± 1.97 vs. –0.80 ± 1.66)) and joint pain when changing direction ( p = 0.026 (–1.87 ± 2.18 vs. –1.20 ± 2.10)). Conclusion: This was the first clinical trial of 24-weeks duration to show improvement of joint pain in athletes who were treated with the dietary supplement collagen hydrolysate. The results of this study have implications for the use of collagen hydrolysate to support joint health and possibly reduce the risk of joint deterioration in a high-risk group. Despite the studys size and limitations, the results suggest that athletes consuming collagen hydrolysate can reduce parameters (such as pain) that have a negative impact on athletic performance. Future studies are needed to support these findings.

A retrospective examination of theory use in nutrition education

Abstract The purpose of this study was to examine the literature in nutrition education research in order to identify changes in the frequency of theory- or model-driven research in the past ten years, as well as to identify the specific theories and models that authors have used. All papers in the Journal of Nutrition Education and abstracts in Dissertation Abstracts that reported any data collection during the years 1980–1990 (n = 346) were read and coded into categories of theory/model use or no use. Studies that utilized theory and/or models were further divided into five subcategories using Gowins educative commonplaces. These subcategories included teacher, learner, curriculum, governance, and other. Results indicate that three-fourths of the studies do not explicitly use a theory or model to select variables or methods or to interpret the results. This proportion has stayed constant over the decade, even with an increase in the number of studies reported. Most of the theories used are drawn from the psychological literature. Alternative theories are presented. The need for a set of theories is emphasized to better address the issues pertinent to nutrition education research.

Flavored Milk, Dietary Quality, and Childhood Nutrition

In the general debate surrounding added sugars in the diet, what is typically lost is the rational appreciation for the fact that a moderate amount of added sugars may actually improve the nutritional quality of any given diet. In fact, moderate amounts of sugar added to nutrient-dense foods have been shown to enhance palatability, increasing the likelihood of their consumption, particularly among children. A case in point could be a basket of juicy, red strawberries. Clearly the berries are ripe, but upon tasting them, they’re found out to be tart. But if they were dipped in table sugar to sweeten them up, they become edible! The sugar made them more palatable. Less than a teaspoon of sucrose was used, in other words, less than 15 cal. But the small amount of sugar used meant the strawberries were eaten versus thrown away. Vitamin C, vitamin A, fiber, and an excellent source of many phytonutrients are ingested as a result. Indeed, the sweetness of naturally occurring sugars found in fruit is what attracted our prehistoric ancestors to consume fruits and other sweet tasting foods, which in turn increased their intake of carbohydrates, vitamins A and C, fiber, and the myriad of phytochemicals we are only now beginning to understand.

Dietary Habits of Two Olympic Female Athletic Teams

Abstract LEARNING OUTCOME: To identify four key strategies for promoting optimal performance in world class female athletes. Female athletes tend to restrict energy to lose or maintain wt. Low intake of total energy may influence micronutrient intake. Dietary composition, such as >60% kcal from carbohydrates (CHO) can negatively influence protein and fat, compromising training and performance outcomes. US Womens Soccer (S) and Field Hockey (FH) Teams (N=54), ranked 1st and 2nd in the world respectively, completed 3-day food records, attended 2 nutrition education sessions and a grocery shopping tour, and had individual nutrition consults during Jan. and April, ‘96. Mean energy intake was 2500 kcal/day based on self-reported food records. Mean hours of daily practice=7. Supplements were used by 14% of FH players and 100% of S Players. Adequate fruit and vegetable intake, based on Food Guide Pyramid recommendations, was met by 16%. Misconceptions pertaining to CHO and protein were noted by 100% of athletes. Disordered eating was identified on both teams. Grocery shopping tours assisted in food selection and reinforced nutrient composition lessons. Follow-up phone conversations revealed a positive change in food selection patterns with regard to all food groups and fat. Nutrition education for Olympic athletes must be improved at the level of each National Governing Body within the US Olympic Committee. R.D.s who maintain expertise in athletics are positioned to assume roles with teams who have not identified dietitians as an integral part of the training program.

PHYSIOLOGICAL ADAPTATIONS TO A WEIGHT-LOSS DIETARY REGIMEN AND EXERCISE PROGRAMS IN WOMEN 267

Thirty-one women (mean age 35.4 +/- 8.5 yr) who were overweight were matched and randomly placed into either a control group (Con; n = 6), a diet-only group (D; n = 8), a diet+aerobic endurance exercise training group (DE; n = 9), or a diet+aerobic endurance exercise training+strength training group (DES; n = 8). After 12 wk, the three dietary groups demonstrated a significant (P </= 0.05) reduction in body mass, %body fat, and fat mass. No differences were observed in the magnitude of loss among groups, in fat-free mass, or in resting metabolic rate. The DE and DES groups increased maximal oxygen consumption, and the DES group demonstrated increases in maximal strength. Weight loss resulted in a similar reduction in total serum cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol among dietary groups. These data indicate that weight loss during moderate caloric restriction is not altered by inclusion of aerobic or aerobic+resistance exercise, but diet in conjunction with training can induce remarkable adaptations in aerobic capacity and muscular strength despite significant reductions in body mass.