Dietary protein and exercise have additive effects on body composition during weight loss in adult women

This study examined the interaction of 2 diets (high protein, reduced carbohydrates vs. low protein, high carbohydrates) with exercise on body composition and blood lipids in women (n = 48, approximately 46 y old, BMI = 33 kg/m(2)) during weight loss. The study was a 4-mo weight loss trial using a 2 x 2 block design (Diet x Exercise). Diets were equal in total energy (7.1 MJ/d) and lipids ( approximately 30% energy intake) but differed in protein content and the ratio of carbohydrate:protein at 1.6 g/(kg . d) and <1.5 (PRO group) vs. 0.8 g/(kg . d) and >3.5 (CHO group), respectively. Exercise comparisons were lifestyle activity (control) vs. a supervised exercise program (EX: 5 d/wk walking and 2 d/wk resistance training). Subjects in the PRO and PRO + EX groups lost more total weight and fat mass and tended to lose less lean mass (P = 0.10) than the CHO and CHO + EX groups. Exercise increased loss of body fat and preserved lean mass. The combined effects of diet and exercise were additive for improving body composition. Serum lipid profiles improved in all groups, but changes varied among diet treatments. Subjects in the CHO groups had larger reductions in total cholesterol and LDL cholesterol, whereas subjects in the PRO groups had greater reductions in triacylglycerol and maintained higher concentrations of HDL cholesterol. This study demonstrated that a diet with higher protein and reduced carbohydrates combined with exercise additively improved body composition during weight loss, whereas the effects on blood lipids differed between diet treatments.     

Effect of a high-protein,energy-restricted diet on body composition,glycemic control,and lipid concentrations in overweight and obese hyperinsulinemic men and women

BACKGROUND: It is not clear whether varying the protein-to-carbohydrate ratio of weight-loss diets benefits body composition or metabolism. OBJECTIVE: The objective was to compare the effects of 2 weight-loss diets differing in protein-to-carbohydrate ratio on body composition, glucose and lipid metabolism, and markers of bone turnover. DESIGN: A parallel design included either a high-protein diet of meat, poultry, and dairy foods (HP diet: 27% of energy as protein, 44% as carbohydrate, and 29% as fat) or a standard-protein diet low in those foods (SP diet: 16% of energy as protein, 57% as carbohydrate, and 27% as fat) during 12 wk of energy restriction (6-6.3 MJ/d) and 4 wk of energy balance ( approximately 8.2 MJ/d). Fifty-seven overweight volunteers with fasting insulin concentrations > 12 mU/L completed the study. RESULTS: Weight loss (7.9 +/- 0.5 kg) and total fat loss (6.9 +/- 0.4 kg) did not differ between diet groups. In women, total lean mass was significantly (P = 0.02) better preserved with the HP diet (-0.1 +/- 0.3 kg) than with the SP diet (-1.5 +/- 0.3 kg). Those fed the HP diet had significantly (P < 0.03) less glycemic response at weeks 0 and 16 than did those fed the SP diet. After weight loss, the glycemic response decreased significantly (P < 0.05) more in the HP diet group. The reduction in serum triacylglycerol concentrations was significantly (P < 0.05) greater in the HP diet group (23%) than in the SP diet group (10%). Markers of bone turnover, calcium excretion, and systolic blood pressure were unchanged. CONCLUSION: Replacing carbohydrate with protein from meat, poultry, and dairy foods has beneficial metabolic effects and no adverse effects on markers of bone turnover or calcium excretion.     

Body composition, dietary intake, and iron status of female collegiate swimmers and divers

This study determined the effect of training on body composition, dietary intake, and iron status of eumenorrheic female collegiate swimmers (n = 18) and divers (n = 6) preseason and after 16 wk of training. Athletes trained on dryland (resistance, strength, flexibility) 3 d/wk, 1.5 h/d and in-water 6 d/wk, nine, 2-h sessions per week (6400 to 10,000 kJ/d). Body-mass index (kg/m2; P = 0.05), waist and hip circumferences (P < or = 0.0001), whole body fat mass (P = 0.0002), and percentage body fat (P < or = 0.0001) decreased, whereas lean mass increased (P = 0.028). Using dual-energy X-ray absorptiometry, we found no change in regional lean mass, but fat decreased at the waist (P = 0.0002), hip (P = 0.0002), and thigh (P = 0.002). Energy intake (10,061 +/- 3617 kJ/d) did not change, but dietary quality improved with training, as reflected by increased intakes of fiber (P = 0.036), iron (P = 0.015), vitamin C (P = 0.029), vitamin B-6 (P = 0.032), and fruit (P = 0.003). Iron status improved as reflected by slight increases in hemoglobin (P = 0.046) and hematocrit (P = 0.014) and decreases in serum transferrin receptor (P < or = 0.0001). Studies are needed to further evaluate body composition and iron status in relation to dietary intake in female swimmers.     

Weight loss and total lipid profile changes in overweight women consuming beef or chicken as the primary protein source

OBJECTIVE: Conflicting recommendations are prevalent regarding the appropriateness of red meat versus white meat consumption for individuals aiming to reduce body weight and cardiovascular disease risk. METHODS: We examined changes in body weight and lipid profiles in a 12-wk, randomized, controlled trial, in which overweight women followed a hypocaloric diet with lean beef or chicken as the primary protein source, while participating in a fitness walking program. Sedentary non-smoking females (n = 61), age 43.4 +/- 7.8 years, with body mass indexes of 32.1 +/- 3.4 kg/m(2) (means +/- standard deviation), followed calculated-deficit diets (-500 kcal daily) and were randomly assigned to the beef-consumption or chicken-consumption dietary group, while following a fitness walking program. Body weight, body composition (by hydrodensitometry), and blood lipid profiles were measured at baseline and 12 wk. RESULTS: Weight loss was significant within (P < 0.05) but similar between (P > 0.05) the beef-consumption (5.6 +/- 0.6 kg, mean +/- standard error) and the chicken-consumption (6.0 +/- 0.5 kg) groups. Both groups showed significant reductions in body fat percentage (P < 0.05) and total (P < 0.05) and low-density lipoprotein (P < 0.05) cholesterol, with no significant differences between groups. High-density lipoprotein cholesterol did not change significantly in either group. CONCLUSIONS: These findings demonstrated that weight loss and improved lipid profile can be accomplished through diet and exercise, whether the dietary protein source is lean beef or chicken.     

Long-term leucine supplementation reduces fat mass gain without changing body protein status of aging rats

ObjectiveAging is characterized by alterations in body composition such as an increase in body fat and decreases in muscle mass (sarcopenia) and bone density (osteopenia). Leucine supplementation has been shown to acutely stimulate protein synthesis and to decrease body fat. However, the long-term effect of consistent leucine supplementation is not well defined. This study investigated the effect of leucine supplementation during aging.MethodsSix-month-old rats were divided into three groups: an adult group (n = 10) euthanized at 6 mo of age, a leucine group (n = 16) that received a diet supplemented with 4% leucine for 40 wk, and a control group (n = 19) that received the control diet for 40 wk. The following parameters were evaluated: body weight, food intake, chemical carcass composition, indicators of acquired chronic diseases, and indicators of protein nutritional status.ResultsBody weight and fat were lower in the leucine group after 40 wk of supplementation compared with the control group but still higher than in the adult group. The lipid and glycemic profiles were equally altered in the control and leucine groups because of aging. In addition, leucine supplementation did not affect the changes in protein status parameters associated with aging, such as decreases in body and muscle protein and total serum protein.ConclusionThe results indicate that leucine supplementation attenuates body fat gain during aging but does not affect risk indicators of acquired chronic diseases. Furthermore, supplemented animals did not show signs of a prevention of the decrease in lean mass associated with aging.     

Lean mass loss is associated with low protein intake during dietary-induced weight loss in postmenopausal women

The health and quality-of-life implications of overweight and obesity span all ages in the United States. We investigated the association between dietary protein intake and loss of lean mass during weight loss in postmenopausal women through a retrospective analysis of a 20-week randomized, controlled diet and exercise intervention in women aged 50 to 70 years. Weight loss was achieved by differing levels of caloric restriction and exercise. The diet-only group reduced caloric intake by 2,800 kcal/week, and the exercise groups reduced caloric intake by 2,400 kcal/week and expended approximately 400 kcal/week through aerobic exercise. Total and appendicular lean mass was measured using dual energy x-ray absorptiometry. Linear regression analysis was used to examine the association between changes in lean mass and appendicular lean mass and dietary protein intake. Average weight loss was 10.8+/-4.0 kg, with an average of 32% of total weight lost as lean mass. Protein intake averaged 0.62 g/kg body weight/day (range=0.47 to 0.8 g/kg body weight/day). Participants who consumed higher amounts of dietary protein lost less lean mass and appendicular lean mass (r=0.3, P=0.01 and r=0.41, P<0.001, respectively). These associations remained significant after adjusting for intervention group and body size. Therefore, inadequate protein intake during caloric restriction may be associated with adverse body-composition changes in postmenopausal women.     

A high dairy protein, high-calcium diet minimizes bone turnover in overweight adults during weight loss

Weight loss induces bone resorption and this can be attenuated by calcium supplementation. Protein-rich diets were recently associated with favorable effects on bone density, although this remains controversial. We hypothesized that a diet high in calcium and protein would minimize bone resorption during weight loss compared with a lower calcium, protein-rich diet. The effects of dietary calcium in high protein diets on calcium excretion and bone metabolism were examined in overweight adults (n = 50, BMI 33.4 +/- 2.1 kg/m(2)) during 12 wk of energy restriction followed by 4 wk of energy balance. Subjects were randomly assigned to isoenergetic diets (5.5 MJ/d, 34% energy from protein, 41% carbohydrate, 24% fat) high in either dairy protein (DP, 2400 mg Ca/d) or mixed protein sources (MP, 500 mg Ca/d). During energy restriction, weight loss was 10% (-9.7 +/- 3.8 kg, P < 0.01), and 24-h urinary calcium excretion decreased independently of diet (-1.09 +/- 0.23 mmol/d, P < 0.01). By wk 16, the MP diet group had a 40% greater increase in deoxypyridinoline (bone resorption marker) than the DP diet group (P = 0.008). Osteocalcin (bone formation marker) increased from wk 0 to 16 in only the MP diet group [+2.16 +/- 0.63 micro g/L (+0.63 +/- 0.11nmol/L), P = 0.001]. In conclusion, weight loss was associated with increased bone resorption, yet the DP diet had a modest advantage over the MP diet by minimizing overall turnover. Combined with reduced urinary calcium excretion, this suggests that a high-protein, calcium-replete diet may protect against bone loss during weight reduction.     

Consumption of fat-free fluid milk after resistance exercise promotes greater lean mass accretion than does consumption of soy or carbohydrate in young, novice, male weightlifters

BACKGROUND: Acute consumption of fat-free fluid milk after resistance exercise promotes a greater positive protein balance than does soy protein. OBJECTIVE: We aimed to determine the long-term consequences of milk or soy protein or equivalent energy consumption on training-induced lean mass accretion. DESIGN: We recruited 56 healthy young men who trained 5 d/wk for 12 wk on a rotating split-body resistance exercise program in a parallel 3-group longitudinal design. Subjects were randomly assigned to consume drinks immediately and again 1 h after exercise: fat-free milk (Milk; n = 18); fat-free soy protein (Soy; n = 19) that was isoenergetic, isonitrogenous, and macronutrient ratio matched to Milk; or maltodextrin that was isoenergetic with Milk and Soy (control group; n = 19). RESULTS: Muscle fiber size, maximal strength, and body composition by dual-energy X-ray absorptiometry (DXA) were measured before and after training. No between-group differences were seen in strength. Type II muscle fiber area increased in all groups with training, but with greater increases in the Milk group than in both the Soy and control groups (P < 0.05). Type I muscle fiber area increased after training only in the Milk and Soy groups, with the increase in the Milk group being greater than that in the control group (P < 0.05). DXA-measured fat- and bone-free mass increased in all groups, with a greater increase in the Milk group than in both the Soy and control groups (P < 0.05). CONCLUSION: We conclude that chronic postexercise consumption of milk promotes greater hypertrophy during the early stages of resistance training in novice weightlifters when compared with isoenergetic soy or carbohydrate consumption.     

Very low-fat (12%) and high monounsaturated fat (35%) diets do not differentially affect abdominal fat loss in overweight, nondiabetic women

Studies in women with type 2 diabetes demonstrated adverse effects on body fat distribution of a low-fat diet relative to a high monounsaturated fat diet. We performed a randomized 12-wk parallel design study of two 6000-kJ diets: 35% energy from fat (high monounsaturated fat diet, HIMO), or 12% energy from fat (very low-fat diet, VLF) to determine whether this also occurred in nondiabetic women. Body fat distribution, fasting plasma glucose, blood pressure, and fasting serum lipids were measured at wk 0 and 12 in 62 women (BMI > 27 kg/m(2)). Weight loss (9.5 +/- 2.4 vs. 9.4 +/- 3.4 kg, VLF vs. HIMO) and total fat loss (6.1 +/- 2.4 vs. 6.3 +/- 2.7 kg, VLF vs. HIMO) did not differ in the groups. There was a diet x menopausal status interaction in lean mass changes (P = 0.005) such that in premenopausal women, HIMO produced a lower loss of lean mass than the low-fat diet (0.4 +/- 2.3 vs. 2.9 +/- 2.7 kg, P = 0.006) with the opposite but nonsignificant effect seen in postmenopausal women. There was a greater decrease in total plasma cholesterol in women who consumed VLF compared with those who consumed HIMO (0.82 +/- 0.0.51 vs. 0.50 +/- 0.48 mmol/L, P < 0.001 for time, P < 0.05 for diet effect). This was also true for the change in HDL cholesterol (0.18 +/- 0.23 vs. 0.04 +/- 0.19 mmol/L, VLF and HIMO, respectively, P < 0.001 for time, P < 0.05 for diet effect). The LDL/HDL ratio was reduced in both groups with no effect of diet (0.16 +/- 0.51 vs. 0.16 +/- 0.45, VLF and HIMO, respectively, P < 0.05). In conclusion, weight, total fat mass, and regional fat mass loss did not differ in the 2 groups of women but there was an apparent preservation of lean mass in premenopausal women consuming HIMO.     

Efficacy of orlistat 60 mg on weight loss and body fat mass in US Army soldiers

A higher body mass index is associated with exercise-related injuries and increased risk for musculoskeletal and connective tissue disorders, which are relevant to military personnel. Studies show the efficacy of orlistat 60 mg for promoting weight and body fat loss in civilians; however, its efficacy among predominantly young, male soldiers is unknown. This study's objective was to examine the effect of a 6-month, standard education-based weight-management program with and without orlistat 60 mg on changes in weight and body fat in overweight soldiers. Data were collected for this randomized, controlled trial from March 2008 to November 2010 at Fort Bragg, NC. Participants were enrolled in an education-based weight management program (n=435; 75% men) and were randomized to placebo or orlistat 60 mg, three capsules daily with meals. All participants were recommended to maintain a reduced-energy, low-fat diet. Among study completers (14% retention rate; placebo n=22, orlistat n=35) members of both groups lost significant weight from baseline (placebo ?3.0±5.2 kg; orlistat ?3.2±4.7 kg; P<0.01), but only the orlistat group lost fat mass (?2.5±3.9 kg; P<0.001), whereas the placebo group lost lean mass (?1.4±2.7 kg; P <0.01). An intent-to-treat analysis (≥1 follow-up body weight measure) demonstrated that the orlistat group lost more fat mass vs the placebo group (?1.3±2.9 kg vs ?0.6±1.8 kg, respectively; P<0.05), but less lean mass (?0.2±2.0 kg vs ?0.8±1.8 kg, respectively; P<0.01). Orlistat 60 mg may be an effective adjunct to an education-based weight management program in a mostly young, male soldier population.     

Exercise intensity does not affect the composition of diet- and exercise-induced body mass loss

The effect of caloric restriction (1200 kcal/d intake) in combination with high (High) (80-90% of peak VO2) or low (Low) (40-50% of peak VO2) exercise work rates on the composition of lost body mass was determined in 27 obese women (percent fat, 36.7 +/- 4.2%; mean +/- SD). All subjects trained 3 d/wk for 8 wk, with the High (n = 14) and Low (n = 13) groups exercising for 25 and 50 min/d, respectively. After posttesting there were no differences between the groups with respect to pre- to posttest changes (mean of combined groups) in body mass (-7%), fat-free mass (-10%), fat mass (-16%), percent fat (-10%), and sum of five skinfold-thickness measurements (-16%). This study suggests that with regard to conservation of fat-free mass, the selection of an exercise intensity for a diet and exercise regimen may be left to the preference of the clinician and/or dieter.     

Effects of dietary protein on the composition of weight loss in post-menopaus al women

Objectives: To determine whether a hypocaloric diet higher in protein can prevent the loss of lean mass that is commonly associated with weight loss.Design: An intervention study comparing a hypocaloric diet moderately high in protein to one lower in protein.Setting: Study measurements were taken at the Wake Forest University General Clinical Research Center (GCRC) and Geriatric Research Center (GRC).Participants: Twenty-four post-menopausal, obese women (mean age = 58 ± 6.6 yrs; mean BMI = 33.0 ± 3.6 kg/m²).Intervention: Two 20-week hypocaloric diets (both reduced by 2800 kcal/wk) were compared: one maintaining dietary protein intake at 30% of total energy intake (1.2–1.5 g/kg/d; HI PROT), and the other maintaining dietary protein intake at 15% of total energy (0.5–0.7 g/kg/d; LO PROT). The GCRC metabolic kitchen provided lunch and dinner meals which the women picked up 3 days per week and ate outside of the clinic.Measurements: Body composition, including total body mass, total lean mass, total fat mass, and appendicular lean mass, assessed by dual energy x-ray absorptiometry, was measured before and after the diet interventions.Results: The HI PROT group lost 8.4 ± 4.5 kg and the LO PROT group lost 11.4 ± 3.8 kg of body weight (p = 0.11). The mean percentage of total mass lost as lean mass was 17.3% ± 27.8% and 37.5% ± 14.6%, respectively (p = 0.03).Conclusion: Maintaining adequate protein intake may reduce lean mass losses associated with voluntary weight loss in older women.     

Intake of major nutrients by women in the Maternal Phenylketonuria (MPKU) Study and effects on plasma phenylalanine concentrations

BACKGROUND: Women with untreated phenylketonuria (PKU) often have poor reproductive outcomes. OBJECTIVE: We assessed the effects of intakes of major nutrients on plasma phenylalanine concentrations and we measured phenylalanine hydroxylase activity and phenylalanine intakes in pregnant women with PKU. DESIGN: Dietary intakes and plasma phenylalanine concentrations were compared in 4 subject groups defined on the basis of plasma phenylalanine concentrations: group 1 (n = 23), <360 micromol/L by 10 wk gestation and 120-360 micromol/L throughout the remainder of pregnancy; group 2 (n = 46), <600 micromol/L but not <360 micromol/L by 10 wk gestation and 120-600 micromol/L throughout the remainder of pregnancy; group 3 (n = 24), <600 micromol/L by 10 wk gestation but >600 micromol/L at least once thereafter; group 4 (n = 147), never <600 micromol/L. RESULTS: Except in the first trimester, mean intakes of phenylalanine, energy, and fat tended to be greater in group 1 than in the other groups. The mean protein intake of group 1 tended to be greater than that of the other groups. Intakes of protein (P < 0.0001), fat (P < 0.0001), and energy (P < 0.007) were negatively correlated with maternal plasma phenylalanine concentrations. It appeared that genotype did not affect phenylalanine tolerance. CONCLUSIONS: Maternal genotype appeared to have little influence on phenylalanine requirements during the first trimester. Early decline and maintenance of maternal plasma phenylalanine concentrations at <360 micromol/L and mean protein intake greater than the recommended dietary allowance (RDA) with mean energy intake near the RDA resulted in the best reproductive outcomes. Inadequate intakes of protein, fat, and energy may result in elevated plasma phenylalanine concentrations and may contribute to poor reproductive outcomes.     

Diet,weight, cytokines and bone health in postmenopausal women

Objectives

To investigate diet and nutrition-related factors associated with bone loss in a group of postmenopausal (PM) women. Nutritional intake, inflammatory markers and body composition (weight, body mass index, fat/lean mass) were analysed for associations with bone mineral density (BMD).

Design

A cross sectional study examining correlations between BMD (Duel-energy X ray absorptiometry; (DXA) and dietary intake (3-day diaries), body composition and plasma bone and inflammatory markers: C-terminal telopeptide of type I collagen (CTX) and procollagen type I N propeptide (P1NP), C- reactive protein (CRP), interleukin 6 and 10 (IL-6, IL-10), tumour necrosis factor (TNF) and osteoprotegerin (OPG).

Setting

Community dwelling women from the Auckland, Hawke’s Bay and Manawatu regions in New Zealand.

Participants

142 healthy, PM women aged 50–70 years.

Results

OPG (per kilogram fat mass) was increased in women with osteoporosis (p<0.001) compared to groups classified with normal BMD and osteopenia. Protein, vitamin B12, zinc, potassium and dairy intake were all positively correlated with higher BMD while dairy and potassium intakes also inversely correlated with CTX. Body composition (weight, BMI and fat/lean mass) had strong positive associations with BMD. Multiple regression analysis showed body weight, potassium and dairy intake were predictors of increased BMD in PM women and explained 39% (r²=0.39, p< 0.003) of variance.

Conclusion

BMD was negatively correlated with OPG and positively with weight, dairy and potassium intake. This study highlights the importance of maintaining adequate body weight and emphasising dairy and potassium predominantly sourced from fruit/vegetables to reduce bone loss at midlife.     

Resting energy expenditure in reduced-obese subjects in the National Weight Control Registry.

BACKGROUND: Weight loss in obese subjects is associated with a reduction in resting metabolic rate (RMR). Whether the reduction can be explained solely by a reduction in lean body mass remains controversial. OBJECTIVE: Our objective was to determine whether the reduction in RMR after weight loss was proportional to the decrease in lean mass alone or was greater than could be explained by body composition. DESIGN: We measured the RMR, fasting respiratory quotient (RQ), and body composition in 40 reduced-obese subjects [ie, 7 men and 33 women who had lost > or = 13.6 kg (30 lb) and maintained the loss for > or = 1 y] enrolled in the National Weight Control Registry and 46 weight-matched control subjects (9 men, 37 women). RESULTS: A stepwise multiple regression found lean mass, fat mass, age, and sex to be the best predictors of RMR in both groups. After adjusting RMR for these variables, we found no significant difference in RMR (5926 +/- 106 and 6015 +/- 104 kJ/d) between the 2 groups (P = 0.35). When we adjusted fasting RQ for percentage body fat and age, the reduced-obese group had a slightly higher (0.807 +/- 0.006) RQ than the control group (0.791 +/- 0.005, P = 0.05). This may have been due to the consumption of a diet lower in fat or to a reduced capacity for fat oxidation in the reduced-obese group. CONCLUSION: These results show that in at least some reduced-obese individuals there does not seem to be a permanent obligatory reduction in RMR beyond the expected reduction for a reduced lean mass.     

Postpartum body composition changes in lactating and non-lactating primiparas.

The objective of this study is to evaluate the postpartum body composition changes in lactating versus non-lactating or formula-feeding primiparas during the first 12 wk. Twenty primiparous females (age range 17-35 y) who decided to nurse or formula feed their infant were studied. The non-lactating mothers (n = 6) were younger (21 versus 29 y) and had a lower prepregnancy weight (55 kg versus 63 kg) than the lactating mothers (n = 14). Body weight, height, waist and hip measurements, 3-d dietary and activity records, skin-fold thickness from triceps, suprailiac, midthigh, and midupper arm circumference, and total body composition were evaluated at three time periods (at delivery, at 6 wk, and at 12 wk postpartum). Total body composition for bone mineral, lean, and fat mass was measured by dual energy x-ray absorptiometry. At delivery and 6 wk postpartum, the weights and heights were similar between the two groups. By 12 wk postpartum, the formula-feeding group had a weight loss that was different from delivery, 66 +/- 10 kg to 59 +/- 8 kg, P < 0.03. There was no significant weight change in the lactating group during the study. The weight loss consisted of more lean mass than fat mass. The total body bone mineral content did not differ between the two groups during the study. Both groups had reduction in their waist size from delivery to 12 wk postpartum. But only the non-lactating mothers had reductions in their hip and midthigh measurements. There were no changes between the two groups in the skin-fold measurements. Lactating mothers had a higher total daily calories (1974 +/- 318 versus 1464 +/- 178 calories, P < 0.002) and fat intake (63 +/- 14 versus 47 +/- 9 g, P < 0.02) than the non-lactating mothers. The energy expenditure was similar between both groups. In conclusion, during the first 12 wk postpartum, non-lactating mothers who were younger and weighed less prepregnancy lost body weight and had more waist, hip, and midthigh size reductions compared to lactating mothers.     

No relation between intakes of calcium and dairy products and body mass index in Japanese women aged 18 to 20 y

OBJECTIVE: This cross-sectional study examined possible associations of intakes of calcium and dairy products to body mass index (BMI; kilograms per square meter) in young Japanese women. METHODS: Subjects were 1905 female Japanese dietetic students who were 18 to 20 y of age. Dietary intake was assessed over a 1-mo period with a validated, self-administered diet history questionnaire. BMI was computed by using self-reported weight and height. BMI among quartiles of energy-adjusted intakes (per 1000 kcal) of calcium and dairy products was compared while controlling for intakes of protein, fat, and dietary fiber, self-reported rate of eating, and other non-dietary variables. RESULTS: Mean BMI +/- standard deviation was 20.8 +/- 2.6 kg/m2. Mean estimated intakes were 268 +/- 93 mg/1000 kcal for calcium and 80 +/- 63 g/1000 kcal for dairy products. Intakes of calcium and dairy products were not significantly associated with BMI (adjusted means in the lowest and highest quartiles were 20.7 and 20.8 for calcium, P for trend = 0.48, and 20.6 and 20.6 for dairy products, P for trend = 0.81). These results were also observed after excluding 481 energy under- and over-reporters for calcium (20.4 and 20.5, respectively, P for trend = 0.73) and dairy products (20.3 and 20.4, respectively, P for trend = 0.73). CONCLUSIONS: Intakes of calcium and dairy products may not necessarily be associated with BMI among young Japanese women who not only are relatively lean but also have a relatively low intake of calcium and dairy products.     

Correlation of a feline muscle mass score with body composition determined by dual-energy X-ray absorptiometry

Body condition scoring (BCS) systems primarily assess body fat. Both overweight and underweight animals may have loss of lean tissue that may not be noted using standard BCS systems. Catabolism of lean tissue can occur rapidly, may account for a disproportionate amount of body mass loss in sick cats and can have deleterious consequences for outcome. Therefore, along with evaluation of body fat, patients should undergo evaluation of muscle mass. The aims of the present study were first to evaluate the repeatability and reproducibility of a 4-point feline muscle mass scoring (MMS) system and second to assess the convergent validity of MMS by dual-energy X-ray absorptiometry (DXA). MMS was as follows: 3, normal muscle mass; 2, slight wasting; 1, moderate wasting; 0, severe wasting. For the first aim, forty-four cats were selected for evaluation based on age and BCS, and for the second aim, thirty-three cats were selected based on age, BCS and MMS. Cats were scored by ten different evaluators on three separate occasions. Body composition was determined by DXA. Inter- and intra-rater agreement were assessed using kappa analysis. Correlation between MMS and BCS, age, percentage lean body mass and lean body mass (LBM) was determined using Spearman's rank-order correlation. The MMS showed moderate inter-rater agreement in cats that scored normal or severely wasted (κ = 0.48-0.53). Intra-rater agreement was substantial (κ = 0.71-0.73). The MMS was significantly correlated with BCS (r 0.76, P < 0.0001), age (r - 0.75, P < 0.0001), LBM (g) (r 0.62, P < 0.0001) and percentage LBM (r - 0.49, P < 0.0035). Additional investigation is needed to determine whether the MMS can be refined and to assess its clinical applicability.     

Effects of calcium and dairy on body composition and weight loss in African-American adults

OBJECTIVE: Our objective was to determine the effects of dairy consumption on adiposity and body composition in obese African Americans. RESEARCH METHODS AND PROCEDURES: We performed two randomized trials in obese African-American adults. In the first (weight maintenance), 34 subjects were maintained on a low calcium (500 mg/d)/low dairy (<1 serving/d) or high dairy (1200 mg Ca/d diet including 3 servings of dairy) diet with no change in energy or macronutrient intake for 24 weeks. In the second trial (weight loss), 29 subjects were similarly randomized to the low or high dairy diets and placed on a caloric restriction regimen (-500 kcal/d). RESULTS: In the first trial, body weight remained stable for both groups throughout the maintenance study. The high dairy diet resulted in decreases in total body fat (2.16 kg, p < 0.01), trunk fat (1.03 kg, p < 0.01), insulin (18.7 pM, p < 0.04), and blood pressure (6.8 mm Hg systolic, p < 0.01; 4.25 mm Hg diastolic, p < 0.01) and an increase in lean mass (1.08 kg, p < 0.04), whereas there were no significant changes in the low dairy group. In the second trial, although both diets produced significant weight and fat loss, weight and fat loss on the high dairy diet were approximately 2-fold higher (p < 0.01), and loss of lean body mass was markedly reduced (p < 0.001) compared with the low dairy diet. DISCUSSION: Substitution of calcium-rich foods in isocaloric diets reduced adiposity and improved metabolic profiles in obese African Americans without energy restriction or weight loss and augmented weight and fat loss secondary to energy restriction.