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Bone Loss Accompanying Voluntary Weight Loss in Obese Humans

– by L. Bjørn et al. (1994). 

Introduction

Some studies have demonstrated that diet-induced weight loss is accompanied by a significant decrease in bone mineral density (BMD). Regional bone changes were not measured. The purpose of the present investigation was to measure changes in total and regional body composition in obese patients undergoing rapid weight loss on a low-calorie regimen.

Methods

Dual-energy x-ray absorptiometry was performed in 51 obese patients before and after 15 weeks on a low-calorie diet (Nupo, yielding 1.9 MJ for women and 2.4 MJ for men for 2 weeks. Thereafter a qualitatively free supplement of food and drink was allowed up to 4.2 MJ for women and 4.7 MJ for men). Of these patients, 39 were scanned 6 months later. Total and regional body bone mineral, fat mass, and fat-free mass were measured. In the control group, 9 normal volunteers were scanned with up to 23 kg lard distributed anteriorly, and 9 volunteers were scanned with 15 kg lard posteriorly. The lard was then gradually removed to simulate the fat loss found in the patient group.

Results

In the patient group, the mean weight loss was 12,273 g, the mean fat loss was 11,014 g, and the mean bone mineral loss was 171.6 g after 15 weeks. A close correlation between the fat loss and bone loss was found and calculated to be 16.5 g bone mineral per kg fat in the patient group, in contrast with 0.5 g bone mineral per kg fat in the control group. In the control group, 15 kg lard placed posteriorly had no statistically significant effect on the bone measurements. If weight and fat were regained at the scanning time 6 months later, the bone mineral was regained as well. Patients with further weight loss continued to lose bone mineral. One patient lost 754 g bone mineral in 9 months. Her weight loss was 45 kg in that period, and the bone mineral content remained within the range for normal women at her age. Methodologic and pathogenetic problems are discussed.

Conclusion

It is concluded that the observed bone loss should be regarded as physiologic normalization within acceptable limits accompanying a diet-induced weight loss in the obese.

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Effect of an energy-restrictive diet, with or without exercise, on lean tissue mass, resting metabolic rate, cardiovascular risk factors, and bone in overweight postmenopausal women.

– by O. L. Svendsen, et al. (1993).

Introduction

Overweight is an independent predictor of cardiovascular disease (CVD) – the leading cause of death and disability in Western societies. Very little is known about the changes in overweight postmenopausal women since all studies previously have been performed in men and pre-menopausal women. Postmenopausal women are at increased risk of CVD; estrogen deficiency, an atherogenic lipid and lipoprotein profile, and fat distribution all play a role. Osteoporosis is another major cause of morbidity and mortality in this group. The consequences of weight reduction from dieting, with or without exercise, on bone in the osteoporosis are unknown. Thus, the aim was to study the effects of an energy-restrictive diet, with or without exercise, on body composition, major cardiovascular risk factors, and bone in overweight postmenopausal women.

Methods

In a longitudinal clinical study, 121 healthy, overweight postmenopausal women (age 53.8 ± 2.5 years, BMI 29.7 ± 3.1 kg/m2) were randomly assigned to 3 groups: control, a 4,200 kJ/d diet, or a 4,200 kJ/d diet with combined aerobic and anaerobic exercise. The diet consisted of an obligatory basis of the formula diet NUPO of 1.6 MJ daily (VLCD) combined with an additional energy com-consumption of up to 2.6 MJ from food freely chosen, according to a “counter diet system”. Body composition (measured by dual-energy x-ray absorptiometry), fat distribution, resting metabolic rate, blood pressure, serum lipids and lipoproteins, bone mineral densities, and markers of collagen and bone turnover were measured before and after 12 weeks of intervention.

Results

One hundred eighteen women completed the study. The mean loss of body weight (9.5 kg versus 10.3 kg, NS) was similar in the intervention groups, but compared with the diet-only group, the diet-plus-exercise group lost more fat (7.8 kg versus 9.6 kg, p ≤0.001) and no lean tissue mass (1.2 kg versus 0.0 kg, p ≤0.001). The resting metabolic rate (per kg wt) was increased in the diet-plus-exercise group compared with the control group (11% versus 4%, p≤0.009). The levels of serum triglycerides, total cholesterol, low-density lipoprotein, and very-low-density lipoprotein decreased, and the ratio of high-density lipoprotein to low-density lipoprotein increased by 20% to 30% in both intervention groups compared with the control group (p≤0.001). The systolic blood pressure dropped, and the waist-to-hip circumference ratio and abdominal-to-total body fat decreased in both intervention groups compared with the control group (10% p≤.003, and 3.5%, p≤0.0001). There were no consistent, major differences between the groups in terms of changes in total body, spinal, or forearm bone mineral densities, or in markers of collagen and bone turnover.

Conclusion

We conclude that, in overweight postmenopausal women, the addition of combined aerobic and anaerobic exercise to a high protein, energy-restricted diet preserves lean tissue mass, promotes physical fitness, and increases the resting metabolic rate and loss of fat. The diet, with or without exercise, led to profound improvements in serum lipids and lipoproteins, blood pressure, and fat distribution. The weight loss induced by the diet, with or without exercise, does not seem to have any major detrimental effect on bone.

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Dietary fiber added to a very low-calorie diet reduces hunger and alleviates constipation

– by A. Astrup et al. (1990).

Introduction

A very low-calorie diet (VLCD) as a nutrition, powder formula diet is being widely used for the treatment of obesity and has been documented to be effective and safe. This regimen facilitates compliance because of its simplicity combined with rapid weight loss, which may further encourage the patient to stick to the diet. The major drawbacks are still the patients’ complaints of hunger between meals, constipation and the infrequency of bowel movements. Recently it has been shown that fibre supplementation to a conventional diet reduces hunger, increases the frequency of bowel movements and softens the consistency of the stools. The supplementation of fibre to a formula diet designed for VLCD has not hitherto been reported.

The purpose of the present investigation was to examine if the addition of fibre to a nutrition powder improves compliance by modifying hunger, satiety, stool consistency and bowel movements. As fibre may impair intestinal absorption of various divalent cations and vitamins, we also monitored plasma levels of the most important metal ions together with other relevant plasma constituents.

Methods

To examine whether supplement of dietary fibre may improve compliance to a very low-calorie diet (VLCD) a nutrition powder (Nupo) providing 388 kcal/day (men: 466 kcal/day) was compared with a similar version containing plant fibre 30 g/day. Twenty-two obese patients entered the study. After a baseline habitual diet, they were randomized to two weeks of treatment in a single-blind design to either VLCD with or without dietary fibre. Subsequently, they were crossed over for a further 2 weeks of treatment.

Results

All 22 patients completed the study without any missed appointments or other deviations from the protocol. The two groups had similar weight losses (about 10 kg/4 weeks), and dietary fibre did not improve this result. During VLCD with fibre, hunger ratings were significantly lower than during VLCD without fibre. Bowel movements decreased from 1.9/day on a habitual diet to 0.7/day on VLCD without fibre but increased to 1.0/day by fibre supplement. No effect of fibre supplementation to satiety, consistency of faeces and flatulence. The supplement of dietary fibre did not influence plasma concentrations of divalent cations like calcium, iron or magnesium, nor did it add any lowering effect on plasma glucose, cholesterol or triglyceride to that of VLCD.

Conclusion

The supplement of dietary fibre to VLCD may improve compliance by reducing hunger and increasing the number of bowel movements, without impairment of absorption of divalent cations.

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