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10/22/2012 Is it in you? Optimal Nutrition for Promoting Physical Activity in Obese Youth Abbie Smith-Ryan, PhD, CSCS*D, CISSN Assistant Professor University of North Carolina Chapel Hill Aims • A discussion of nutrient timing • A detailed look into commonly used sports drinks: their ingredients, their purpose and recommendations. • The role favorite sports drinks may play in meeting the needs of an overweight physically active child. Issues at hand • Childhood obesity has more than tripled in the past 30 years. • This rise follows the increase in SSB’s. • 84% of teens consume SSB ‘s daily – Equivalent to +365 extra calories daily • 50-70% of beverage consumption occurs in homes. 7-15% occurs in schools Wang, C et al. Pediatrics 2008. 1 10/22/2012 Issues at hand • Sugar consumption: – Food & snacks = 1˚ – SSB = 2˚ Beverage (Approximate Calories per 12oz portion) Sports drink 105 Energy drink 165 Juice drink 180 Regular soda Grams of Sugar 140 Phillips, SM. Sports Med 2012: 42 (1): 817-828 Cause of Childhood Obesity? • Result of the classic weight loss paradigm? – Too many calories consumed – Not enough physical activity • Not the whole picture: – Type of calories makes a difference: • Sugar • Protein – Type of exercise makes a difference • EPOC and metabolism – Nutrient timing Calorie Balance Equation • Assumptions include: – Calorie content of food is accurate – Calorie expenditure can be measured accurately – No other factors affect weight management Biggest influence Variable Minor but advantageous 2 10/22/2012 Caloric Expenditure & Exercise Not All Exercise Increases Energy Needs Baseball/Softball Track – Field Events & Sprinting Diving Any Sport with only 2 activity sessions per week Sports That Require Additional Energy Sports training 4 or more times a week HARD Endurance Sports: swimming, running, cycling Team Sports: soccer, lacrosse, football, basketball, lacrosse, ice hockey, field hockey Gymnastics, tennis, fencing, skiing Caloric Expenditure & Exercise • Intensity is the most important factor • Nutrient availability can influence metabolic response • Kids (16-30%) > CHO oxidation than adults (10-20%) Caloric Expenditure & Exercise • Intensity also effects post-exercise caloric expenditure. 3 10/22/2012 “Nutrient – Exercise Timing” Hypothetical Model to Maximize: Fuel Utilization Growth Recovery & Repair Ivy & Portman 2004; Kerksick et al. ISSN 2008, Manore, Meyer & Thompson 2010 ENERGY PHASE ENERGY PHASE PreExercise Workout 15-60 min ANABOLIC PHASE PostExercise 1-2 hours 1 hour GROWTH PHASE (Rapid) GROWTH PHASE (Sustained) Recovery Recovery 5 hours 16-17 hours 24 Hours ENERGY PHASE PreExercise 15-60 min • • • • • Increase nutrient availability Spare muscle glycogen Enhance fat utilization Minimize muscle damage Faster recovery provisions Consume: - Moderate GI CHO before - Small Pro- before/during -Essential AA (e.g., whey) 4 10/22/2012 ENERGY PHASE • • • • • Workout Increase nutrient delivery Spare muscle glycogen Limit immune system suppression Minimize muscle damage Faster recovery provisions Consume: - CHO during exercise 1-2 hours -Liquid, 6-8% CES -Small Pro- before/during -Essential AA (e.g., whey) ANABOLIC PHASE Consume: - High GI CHO post-exercise, immediate -Liquid, 6-8% CES -1.0 to 1.5 g/kg - Pro- post-exercise -3:1; 2:1 CHO to Pro- ratio -Essential AA - Hydration: 1-2 cups fluid (CES/H2O) per lb lost High GI CHO – perfect time to feed ‘sweet things’ PostExercise 1 hour • • • • • • Shift catabolic to anabolic state Speed waste elimination Replenish muscle glycogen Initiate muscle repair-growth Reduce muscle damage Bolster immune system GROWTH PHASE (Rapid) Recovery 5 hours • Maintain: • Insulin sensitivity • Anabolic State Consume: - Small CHO / Pro- feedings -Every 1 to 2 hours post-exercise -3:1; 2:1 CHO to Pro- ratio -Essential AA (e.g., whey, casein) - Food / meals 5 10/22/2012 Consume: -Energy intake -Neutral balance -Positive N balance -Pro- intake (1.0-1.5 g/kg/d) GROWTH PHASE (Sustained) - CHO to repletion glycogen - Food / meals (mixed diet) • Maintain + nitrogen bal • Stimulate protein synthesis • Promote: • Protein turnover • Muscle development Recovery 16-17 hours Hydration Pre-Exercise: • Young athletes should plan on drinking eight ounces of gatorade sports drink an hour or two before physical activity. • About 10 – 20 minutes before the activity, an additional four to eight ounces should be ingested. • Why Gatorade? – Research by Dr. Bar-Or demonstrated in young boys (10-14 years), hydration was maintained better dinking Gatorade versus plain water and favored water while exercise in hot environments. Thought to be due to behavior and physiological reasons. During-Exercise: • While exercising, young athletes should drink three to four ounces of CES/water every fifteen minutes Post-Exercise: • Young athletes should ingest two cups of water for every pound of weight loss. Int J Sport Nutr. 1998 Mar;8(1):1-9. J Appl Physiol. 1999 Jan;86(1):78-84. Fate of Ingesting 1950 ml Solutions after Exercise at 2 Hours Post Ingestion 2.5 2 1.5 Other Urine Retained 1 0.5 0 W ATER CHO/ELECTROLYTE Glucose solution up to 10% without impeding fluid replacement Glucose greater than 10% will delay gastric emptying and compromise fluid replacement (Costill 1977) Gonzalez-Alonso et al. Int J Sports Med. 1992 6 10/22/2012 Whole Foods or Liquid Supplements – Which is Better for Exercise Recovery? • Nutrient timing critical: – For a rapid and complete recovery due to a metabolic window of opportunity • Muscle has residual catabolic activity following exercise, it will rapidly shift from a catabolic state to an anabolic state if the right nutrients are ingested soon after exercise. – Once the metabolic window of opportunity has closed, nutrient supplementation is not as effective in shifting the muscles into an anabolic state Metabolic window of opportunity – The time after exercise in which the muscle is highly capable of responding to the anabolic effects of insulin if sufficient substrate is made available. Without nutrient intervention, the metabolic window begins to close within 45 minutes following exercise • Nutrients that are essential for a rapid and complete recovery are fast-digesting : – Whey and Casein – Amino acids – Electrolytes – High-glycemic carbohydrates • Consuming a liquid supplement as your postexercise recovery nutrition helps start the rehydration process. Whole foods as the recovery meal will slow gastric emptying and will likely delay rehydration 7 10/22/2012 TO DRINK OR NOT TO DRINK? • Gatorade – Prime, Perform, Recover • • • • • G2 Powerade Juice Soda Milk CHO Supplementation in Kids • Pre-exercise & During CHO supplementation: Author Demographics Protocol Supplementation Findings Dougherty MSSE 2006 Male B-Ball (13.5 yrs) 2h intermittent ex + B-ball game 6% CES + water; water – both euhydrated PshooQng accuracy (p<0.05) Carvalho IJSNEM 2011 Male B-Ball (14.8 yrs) 1.5 hour drills & training Ad libitum: 8% CES, water, nothing No significant influence of CES on performance or shooting accuracy Phillips EJAP 2010 M & F multi-sport (12.7 yrs) Intermittent sprinting 6% CES 5ml/kg pre-ex & 2 ml/kg every 15min during vs. H2O 24% longer TTE No effect on sprint Higher HR in CHO grp Phillips EJAP 2012 M & F multi-sport (13.3 yrs) Intermittent sprinting (4 x 15 min) 2%, 6%, 10% pre and during Longer TTE in 6% vs 10% and 2%. 2%> TTE than 10% 8 10/22/2012 Concerns – beyond performance • Dental erosion – Sports beverages = pH similar to diet cola • Linked to dental erosion in adult consumers • Obesity – Numerous articles citing association of SSB & obesity – but don’t quantify physical activity • Mundt et al. MSSE 2006; 38:1245-54– only study to date: – FM inversely associated with physical activity with no significant influence of SSB on fat mass. • Yale Rudd Center for food policy & obesity: SSB synopses and child obesity: no clear CAUSE, but clear association • More research is needed. To drink or not to drink? • Kool-Aid vs. Milk – 8 oz Kool-Aid (108 kcal, 28.8 g CHO/sugar) – 8 oz. 1% milk (102 kcal, 11.7 g CHO, 8 g PRO, 2.6 g FAT) FIGURE 1. • • Figure 3. Figure 5. REE – indirect calorimetry Body Fat • Milk consumption in children induces greater REE, TEF, and RQ. – Greater caloric expenditure – Greater fat utilization St-Onge et al. Metab Clin Exper 56 (2007) 1699-1707 To drink or not to drink? • Randomized controlled trial: – 98 children 8-10yrs regular consuming SSB • 16-week intervention – Milk Group: 3 servings/day (1%) & no SSB – Control: no instruction/dietary changes • DXA for body composition – %body fat – Trunk fat – Lean mass • Significant reduction in SSB – PRO, Calcium increased (p<0.001) – Calories decreased (p=0.009) • No change in %Body fat (p=0.22) or Fat mass (p=0.81) • Significant increase in LBM (p=0.04) – Greater increase in height for boys 9 10/22/2012 Summary & Applications Abbie Smith-Ryan, PhD, CSCS*D, CISSN [email protected] 919-962-2574 10