some dietary issues in exercise: weight control

Some Dietary Issues in Exercise:

Weight Control

Maintaining adequate nutritional status is not much of a problem for healthy & active individuals who eat reasonably well . . .

Things are different, however, when restricting calories . . .

With the Estimated Energy Requirement (DRI) for Adolescents & Adults being so much higher than the caloric intake necessary to get the minimum nutrients . . .

Males(9 yrs – 13 yrs ~ 2250)

14 yrs – 18 yrs ~ 3150

19 yrs – 50 yrs ~ 3050

- subtract 10 kCal / day for each year over 19 yrs

Females(9 yrs – 13 yrs ~ 2100)

14 yrs – 18 yrs ~ 2350

19 yrs – 50 yrs ~ 2400

- subtract 7 kCal / day for each year over 19 yrs

Remember This Healthy Diet Concept:

Number of Food Servings for Daily Caloric Intakes:

Food Group Standard Approximate ~ 2000 ~ 2200 ~ 2500 ~ 2800 Serving Size Calories / kcal kcal kcal kcal

Serving

Fruits 0.5 cup 71 5 5 5 5

Vegetables 0.5 cup 38 6 6 6 6

Cold-Water Fish 4 ounces 120 2/wk 2/wk 2/wk 2/wk

(Lean Meats on 3 ounces 120 - - - -remaining days are optional)

Nuts & Seeds 0.25 cup 240 1 1 1 1

Beans & Legumes 0.5 cup 110 2 3 3 3

Dairy 1.0 cup/2 oz. 86 3 3 3 3

Breads & Cereals 1 slice/1 oz 78 5 6 7 7

Red Wine 4 oz 85 1 1 1 1

Added Fats 1 Tbsp (EVOO) 110 2 2 3 3

Discretionary Calories - - 200 400*1900/2000 kCal intake meets RDA requirements on average; 2200 kCal or more meets or exceeds requirements each day. . . So it just shouldn’t be so difficult

Unfortunately . . . the average non-restricted American diet really sucks . . . especially in the area of fruits and vegetables; major sources of many vitamins and minerals . . .

Adapted from: Nutrition for Sport and Exercise, Dunford & Doyle, 2008

Resulting in an almost non-existent probability of being adequate . . . especially with a calorie-

restricted diet!!!

Adapted from Nutrition for Sport and Exercise, Dunford & Doyle, 2008

Because we really really like to go on weight loss-loss diets . . . And lose weight as fast as possible . . . It is not unusual for us eat 1,000 or 1,200 kCals each day while trying . . . Vitamins and minerals are already a “lost cause”, but even the minimum requirements for the major macronutrients (CHO, AA, FFA) can be at risk . . .

AI 130 g/day45% to 65% of total calories (4 kcal/g)

IOM recommends 1 hour of moderately stressful exercise every day

NRG for moderately stressful exercise is 50 – 80% carbohydrate . . .

6 – 7 mph ~ 600 – 800 kcals @ ~50% ~ 300 – 400 kcals = ~ 75 – 100g additional CHO

Therefore, a logical minimum DRI would be more than the IOM recommendation

~ 200g/day would be a reasonable estimate

AI 0.8 g/kg; 1.0 - 1.4 g/kg with exercise10% to 35% calories (4 kcal/g)

Nitrogen balance studies indicate that more is needed with exercise . . .

. . . labeled infusion studies on the use of amino acids for synthesis and metabolism indicate a decrease in proteolysis / with a maintenance of synthesis following repeated exercise; leading to a reduction in the dietary protein requirement . . . Therefore the IOM recommendation for 1.2 – 1.4 g/kg with moderate to stressful exercise may be somewhat dubious

&

Because average American consumes > 2X DRI already, modifying dietary content of protein also is of dubious benefit…

AI 12 & 17 g/day linoleic acid (C18:2; n6, 9 - all cis): F / M; based on on median intake1.1 & 1.6 g/day α-linolenic acid (C18:3; n9, 12, 15 - all cis) F / M; based on median intakeOr: 10 - 35% of total calories (9kcal/g)… so… lets see what you have to eat to…

Some older texts suggested a minimum total intake of 20g/day to insure a sufficient uptake of fat soluble vitamins which greatly underestimates the actual dietary lipid requirement (RDAs are based on fatty acid intake, not TG intake and eating exactly 12g linoleic acid or 1.1 g α-linolenic acid would obviously necessitate eating more than 13g total fat since the EFA are a small minority of total FFAs)

EFA Content of various foods in % of total FA

Linoleic α-Linolenic % Fat by WtCanola Oil ~ 26 - 100Corn Oil ~ 35 - 65 - 100Olive Oil ~ 3 - 20% ~ 1% 100Palm Oil ~ 6 - 12 ~ 0.5 100Peanut Oil ~ 14 - 43 ~ 0.4 100Flax Oil ~ 14 ~ 50 - 60 100Beef (grain-fed-trimmed) ~ 3.4 ~ 0.4 ~ 5Beef (grass-fed-trimmed) ~ 4.4 ~ 1.2 ~ 2.5Chicken (skinless-breast) ~ 21 ~ 0.9 ~ 4.5Salmon (Norway-wild) ~ 1 ~ 1 (2%EPA/20% DHA) ~ 3 - 4

Human Milk ~7 - 18 ~ 1 ~ 2 - 4Cow Milk Fat ~ 2.6 ~ 1.6 ~ 0, 1, 2, or ~3.5

Based on the EFA content of common foods (as a percent of total fatty acids) you clearly have to eat a lot more grams of fat than the RDA (as expressed in grams for the EFA’s) – 60 g/day would not be an outlandish minimum estimate.

SummaryMinimum Macronutrient Intakes:Carbohydrate: ~ 200g/d = 800 kCalProtein: ~ 0.8 g/kg/d (~60 g?) = 240 kCalLipid: ~ 60 g/d = 540 kCal

Total kCal = 1580

At 1900 kCal (following the recommended servings): Recommended % (IOM)

carbohydrate = ~ 250g (55%) 45% - 65%protein = ~ 70g (16%) 12% - 20%lipid = ~ 60g (30%) 20% - 35%

At 1200 kCal (cutting the recommended servings to exactly 63%):carbohydrate ~ 157gprotein ~ 44glipid ~ 37g

At this intake, protein is below the minimum AI for a sedentary person . . . And carbohydrate is below the minimum recommended for an active person . . . And fat is below a “reasonable minimum”…

Obviously, the “average” American who attempts a weight-loss diet will be deficient in something in a very short time - especially if they go on one of those fad diets that severely restrict one of the major macronutrients; such as the Atkin’s diet.

The best solution is to first revise the diet to be consistent with the recommended array of servings:

See recommended servings for. . . And then introduce physical activity (500 kCal minimum) . . . And then monitor weight and skinfolds . . . And then figure out what to do; adjust servings (trial & error) . . .

Number of Food Servings for Different Daily Caloric Intakes________________________________________________________________________________________________________________

Standard Average *Required Recommended Serving kcal/

Food Group Size Serving ~1900 kcal ~2200 kcal ~ 2500 kcal ~ 2800 kcal________________________________________________________________________________________________________________

# Servings ____________________________________________________

Fruits 0.5 c. 71 4 4 5 6

Vegetables dark green 0.5 c. 20 2 2 3 3 deep yellow 0.5 c. 38 1 1 2 2 starchy 0.5 c. 76 1 1 1 2 other 0.5 c. 18 2 3 3 3

Meat/Fish/Eggs 3 oz. 165 0 1 1 1 Beans/Legumes 0.5 c. 110 2 3 3 3Nuts/Seeds 0.33 c./0.25 c. 240 1 1 1 1

Dairy (skim/low-fat) milk/yogurt 1 c. 86 3 3 3 3 cheese ~ 2 oz.

Breads/Cereals 0.5 c. 78 5 6 7 9 (whole grain/fortified) 1 slice

Added Fats 1 Tbsp. 100 2 2 2 3

*Red Wine 4 oz. 85 1 1 1 2________________________________________________________________________________________________________________The ~1900 kcal recommendation follows the minimum required number of servings from each food category as described in the Optimal Health Guide. Caloric values are based on the tabled values for nutrient and caloric content of food servings available in the 2005 IOM and USDA recommendations. These values are based on averaged values from mixed food servings from the North American diet and should be considered to be reasonable estimates.

*Can safely be removed from the minimum without compromising nutrient intake to produce a ~ 1800 kcal intake.

Calories Burned For 30 Minutes Exercise*________________________________________________________________________________________________________Exercise Approximate Calories Burned for the Indicated Body Weight

Intensity________________________________________________________________________________________________________

110 lbs 150 lbs 190 lbs _____________________________________________

Bicycling Hard (fastest possible) 255 350 445Moderate (~ 10 mph) 165 225 285Easy (~ 5 mph) 90 120 152

Running 10 mph 415 565 715 8 mph 350 475 600 6 mph 265 360 455

Weight Lifting Hard 175 240 305Moderate 130 175 225

Stationary Rowing Hard 270 370 465Moderate 180 245 310

Aerobics Hard 205 280 350Moderate 165 225 285

Swimming Hard 550 750 950Easy 165 225 285

Basketball Moderate 150 205 260

Golf Carrying 130 180 225Cart 110 150 190

Rollerblading Hard 270 370 465Moderate 235 320 400

Walking 4.5 mph 170 235 2953.5 mph 125 175 2202.5 mph 95 130 165

________________________________________________________________________________________________________

*Please note that these caloric-expenditure values are approximate only. Everyone is different and some people may burn as muchas 15% fewer than these values or 15% more than these values and the value amount will change with training & diet.

Be absolutely “anal” about counting & measuring servings and tracking your minutes of exercise activities every day.

After a few weeks you will have a good idea about your estimated average calorie intake and your estimated average exercise calorie output.

Try moving toward the minimum-servings diet plan… as long as you stay near the minimum servings/day (w/o wine) your intake will be around 1800 kcal/day and developing a nutritional deficiency will be minimized. See what happens…

Adjust exercise minutes and/or servings every couple weeks to see what happens & to produce a weight-loss of no more than 2 pounds/week - there should be no hurry!

Total Fat & Muscle Loss ~ 12 lbs~ 4 lbs/week

Total Fat Loss ~ 8 lbsTotal Lean Mass Loss ~ 4 lbs

NOT really a good thing - Lose 8 lbs fat in 3 weeks and lose 4 lbs of indispensable tissue along

with it!!

2000 kcal/day Caloric Deficit

Week Body Mass % Body Fat Total Fat Fat Loss Lean Loss

0 162 18% 29.16 lbs - -

1 158 17% 26.86 2.30 lbs 1.70 lbs

2 154 15% 23.10 3.76 lbs 0.24 lbs

3 150 14% 21.00 2.10 lbs 1.90 lbs

Too Much - Too Fast!

Total Fat & Muscle Loss ~ 8 lbs~ 2 lbs/week

Total Fat Loss ~ 7.4 lbsTotal Lean Mass Loss ~ 0.6 lbs

A much better result - Lose 7.4 lbs fat over 4 weeks

and only 0.6 lbs of the good stuff

1000 kcal/day Caloric Deficit

Week Body Mass % Body Fat Total Fat Fat Loss Lean Loss

0 161 18% 28.80 lbs - -

1 159 17% 27.03 lbs 1.77 lbs 0.23 lbs

2 157 16% 25.12 lbs 1.91 lbs 0.09 lbs

3 155 15% 23.25 lbs 1.87 lbs 0.13 lbs

4 153 14% 21.42 lbs 1.83 lbs 0.17 lbs


Negative Calorie Balance

(Eating Disorders and Disordered Eating)

Throwing stressful exercise into the mix seems to really screw things up . . .

The Female Athletic Triad is a good example of how things appear to be something they are not:

- Disordered eating

- Amenorrhea

- Osteoporosis

Primary (ONLY?) cause is disordered eating

Disordered Eating - Some Data:

- low-energy diet ie. a negative energy balance: anorexia nervosa (1.3%), bulimia nervosa (8%), anorexia athletica (8.2%, of elite female athletes in 1993 Norwegian survey); 5.6% AN/NB in

collegiate athletes with ~30% at risk in 2002 survey…

Disordered eating is common in weight-sensitive sports: gymnastics, light-weight rowing, martial-arts, ballet, distance running, diving, figure skating …

- eating disorders are usually considered obsessive: AN & BN are obsessive, disordered eating (AA) is usually not

- chronic caloric deficits force physiological adaptation

- chronic caloric deficits in face of “normal american diet” imply nutritional deficits as well

- amenorrhea and osteoporisis result from the physiological adaptations to calorie (& nutrient) deficits

Athletic Triad: presence of Disordered eating + Amenorrhea + Osteoporosis:

- Elite athletes 4.3% (14 hours stressful exercise / week)

- Active controls 3.4% (~ 5 hours exercise / week)

Disordered eating + menstrual dysfunction:

- Elite athletes: 26.9%

- Active controls: 13.8%

Disordered eating + low BMD



Menstrual dysfunction + low BMD



Add it all together and ~ 47% elite and ~ 45% control athletes could have a problem!

Negative Energy Balance & Amenorrhea

Eating insufficient calories leads to amenorrhea

studies document women athletes who are amenorrheic eat the same or fewer calories each day than non-active women

decreased T3 and Leptin are observed in women with “athletic-amenorrhea” and both are directly associated with negative caloric balance

prolonged negative energy balance leads to decreased GnRH, LH, and ultimately: ovarian failure, resulting in lower estrogen levels and higher prolactin levels; both of which lead to amenorrhea

The endocrine response to negative caloric balance also affects bone cells

Reduced estrogen and enhanced cortisol are major endocrine responses to starvation that can directly effect bone cell function.

Major bone cells:

Osteoclasts: bone resorption

Osteoblasts: bone deposition

- bone remodeling: a couple weeks of resorption by osteoclasts which then die through apoptosis

- followed by 3 – 4 months of new deposition by osteoblasts to fill in the cavity left by the osteocytes and then most die through apoptosis while some differentiate into osteocytes

- it takes up to a few years for complete re-mineralization of the new bone.

The endocrine response to negative caloric balanceaffects the bone cells

Estrogen normally inhibits osteoclast function to limit the rate of bone resorption as well as the development of pre-osteoclasts into osteoclasts

Estrogen also decreases local production of IL-6, IL-1, and TNF, all of which enhance the development of osteoclasts from precursor cells

Therefore:

Reduced estrogen due to starvation greatly enhances bone resorption

(Add in a nutritional deficit from a lousy diet and you then have a real big problem!!)

Cortisol levels increase as a result of a negative calorie balance in order to enhance gluconeogenesis . . .

Cortisol also enhances rates of apoptosis in osteoblasts, reducing bone formation.

Therefore; as a result of low estrogen and high cortisol, both of which are starvation responses,

osteoporosis will develop . . .

. . . So, lets look at some nutritional aspects of bone formation to see why osteoporosis is so common . . .

Major Nutrients That Are Important For Bone Formation Include:

Adult RDA or AI Median Intake (USA) - NHANESIII ♂ ♀ ♂ ♀

Calcium teen 1300 mg 1000 mg ~ 1000* ~ 650adult 1000 mg 1000 mg ~ 850 ~ 600

Phosphorus 700 mg 700 mg ~ 1450 ~ 1,000

Magnesium 18 – 30 yrs 400 mg 310 mg 9+ yrs 31 – 50 yrs 350 mg 265 mg ~ 310 ~ 220

Vitamin D 5 µg 5 µg n/a

Vitamin K 120 µg 90 µg ~ 105 ~ 85

Vitamin C 90 mg 75 mg ~ 120 ~ 90

Vitamin A 900 µg 700 µg ~ 1,000RE ~ 800RE

Zinc 11 mg 8 mg ~ 14 ~ 9

Copper 900 µg ~ 1400 ~ 1000

Iron 8 mg 18 mg ~ 17 ~ 12

*25+ % prevalence of deficient intake

Major Nutrients That Are Important For Bone Formation include:

Calcium : component of hydroxyapetite

Phosphorus : component of hydroxyapatite

Magnesium : necessary for binding of PTH to receptor & crystallization of matrix

Vitamin D : 1,25 dOH-D3 (calcitrol): hormone to initiate transcription of Ca++- binding proteins

Vitamin K : necessary co-factor for gamma-glutamyl carboxylase; post- translational modification for Ca++-binding properties (osteocalcin)

Vitamin C : necessary co-factor for proline and lysine hydroxylase for procollagen synthesis

Vitamin A : RxR binding and osteoclast maturation

Zinc : a component of alkaline phosphatase that enhances microavailability of phosphorus for mineralization

Copper : a component of lysyl oxidase for crosslinking of collagen fibers

Iron : a component of lysine and proline hydroxylase for stabilization of procollagen synthesis collagen

Hematopoietic Stem Cells: bone marrow stem cells that can differentiate into lymphocytes, granulocytes, monocytes, erythrocytes, osteoclasts . . .

Mesenchymal Stem Cells: bone marrow stem cells that can differentiate into osteoblasts, chondrocytes, myocytes, adipocytes. . .

From your extensive knowledge of nutrition stuff (including specific nutrient sources - that would be individual foods) be prepared to design food intake resource tables (specific foods, RDA/AIs, and food groups), to illustrate “how easy” it is to enhance calcium, magnesium, vitamin K, and iron in the diet for adult female athletes ...

Oh yeah! . . . Include zinc and folic acid as well . . . Just for fun (see next)

And oh yeah again . . . You may want to be the nutritionist and include specific functions of the nutrients in the same resource tables . . .


Anemias

Anemias

Iron deficiency can lead to anemia; a reduced volume of RBC’s in the blood with obvious implications for oxygen-carrying capacity of the blood and alterations in performance capacity . . . iron deficiency without anemia still reduces performance

In addition to iron deficiency, anemias also are associated with vitamin B12 deficiency, folic acid deficiency, or extensive RBC hemolysis (can occur with endurance running)

Iron deficiency : microcytic anemia due to inability to anemia synthesize sufficient hemoglobin

Symptoms include: fatigue / paleness / irritability / tachycardia / pica / sore & swollen tongue

B12 and/or folic acid deficiency : macrocytic anemia due to insufficient anemia DNA synthesis for cell proliferation

during hematopoesis

Symptoms include: nausea / weakness / fatigue / numbness or tingling in hands and feet / decreased appetite & weight loss / diarrhea / tender tongue – not swollen

Some Major Nutrients That Are Important For RBC Formation Include:

Adult RDA or AI Median Intake (USA) - NHANESIII ♂ ♀ ♂ ♀

Phosphorus 700 mg 700 mg ~ 1450 ~ 1,000

Magnesium 18 – 30 yrs 400 mg 310 mg 9+ yrs 31 – 50 yrs 350 mg 265 mg ~ 310 ~ 220

Zinc 11 mg 8 mg ~ 14 ~ 9

Iron 8 mg 18 mg ~ 17 ~ 12

Folic Acid 400 µg unknown / ~ 10% deficiency in USA

B12 2.4 µg ~ 4.5 ~ 3

Choline 550 mg 425 mg unknown

B6 1.3 mg ~ 1.9 ~ 1.5

*25+ % prevalence of deficient intake

Some Major Nutrients That Are Important For RBC Formation include:

Phosphorus : essential component of nucleotides

Magnesium : necessary for (genomic) DNA synthesis and repair - facilitates binding

Cobalamine (B12) : necessary for conversion of methyltetrahydrofolate to tetrahydrofolate

Zinc : a component of delta-aminolevulinic acid dehydratase for heme synthesis, zinc-finger motifs of promoters

Iron : necessary for heme synthesis

Folic Acid : necessary for thymidylate synthesis (DNA synthesis) & methylation of t-RNA

Choline : methyl transfer for betaine synthesis in B12/folate cycling for DNA synthesis

B6 : a component of delta-aminolevulinic acid synthase

(Production of Erythrocytes)

In order for high rates of RBC synthesis to be maintained, high rates of DNA and protein (including hemoglobin) synthesis are necessary . . .

You’ve seen this before . . .

Only now it is labeled with some nutrient requirements

some dietary issues in exercise: weight control

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