BS371 NUTRITION AND DRUGS IN SPORT AND EXERCISE Anna Wittekind

Overview  How the lectures are organised  Read relevant lecture in BS153  Module Guide  Reading list  Assignment – next lecture  Exams

The athlete’s diet  What are the special nutritional needs of athletes in training? Carbohydrate 60-70%Carbohydrate 60-70% Lipid20-25%Lipid20-25% Protein10-15%Protein10-15%

What should they be eating? ACSM Position Stand (2000) - Nutrition and athletic performance. ACSM Position Stand (2000) - Nutrition and athletic performance.  core/template- journal/msse/media/1200.pdf core/template- journal/msse/media/1200.pdf core/template- journal/msse/media/1200.pdf  Burke, L. (2007) IAAf Concensus on Nutrition for Athletes: Updated Guidelines. IJSNEM 17 (4):

Energy requirements  During times of high-intensity training, adequate energy needs to be consumed to  maintain body weight,  maximize the training effects, and  maintain health.  Low-energy intakes can result in  loss of muscle mass,  menstrual dysfunction,  loss or failure to gain bone density, and  increased risk of fatigue, injury, and illness.  (ACSM Position Stand)

Do athletes achieve the guidelines?  Questions

Measuring energy expenditure  TDEE = RMR (REE) + TEF + TEA  + any additional costs (growth, pregnancy, lactation)  e.g. 70 kg male runner  runs 10 miles per day at a 6-min/mile  Requires ~ 1,074 kcal per day for running (17.9 kcal/min) +  energy cost of normal daily activities (2900 kcals)  Thus, this athlete would need approximately 3,974 kcal.d -1.  Tour de France ~7,000 kcal.d -1  But….

Energy in vs Energy out

Number of minutes to use up 400kJ of energy:

How do we measure energy expenditure?  Indirect calorimetry  DLW  Factorial method using prediction equations based on rmr + energy cost of daily activities  e.g.  Cunningham (1980)  RMR = (lbm)  Harris Benedict (1919)  E.g. Males RMR = (bm) + 5(ht) – 6.76 (age)

How do we measure energy expenditure?  RMR x activity factor (Manore and Thompson, 2006)  e.g.  Resting – RMR x 1  Moderate – walking 3.5 – 4 mph, slow cycling…. RMR x 4  Very strenuous – race pace swimming, cycling …… RMR x 10

Measuring dietary intake  Dietary history  Dietary recall  FFQ  Food record/diary

Energy balance?  Many situations of apparent energy imbalance  Body mass/composition  Does energy deficit reflect  Undereating and/or  Underrecording

Energy availability  Can energy intake support health and performance?  = dietary energy available to the body after energy cost of daily exercise taken into account (Loucks 2004)  45 kcal.kg -1 lbm.d -1  <30 kcal.kg -1 lbm.d -1   -ve effects on metabolism and menstrual function (Loucks and Thuma, 2003),  ↓ resorption/formation bone (Ihle and Loucks, 2004)  ↓ metabolic/sexual hormones ♂ (Friedl et al., 2000)