Weight cycling in female rats subjected to varying meal patterns

Wheeler, James M.; Martin, Rachel E.; Lin, Ding; Yakubu, F.; Hill, James O.

doi:10.1152/ajpregu.1990.258.1.r124

Cited by 8 publications

(7 citation statements)

References 6 publications

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“…This combination has been reported to predispose both humans and animals to weight gain and fat accumulation (14,20,21,55). Although SUB recovered some body weight during recovery, their body weight never reached that of CON despite being hyperphagic.…”

Section: Discussionmentioning

confidence: 92%

“…For example, consuming many small meals throughout the day decreases body weight relative to consuming the same number of calories as a few large meals (21). Conversely, taking fewer, larger meals promotes the gain of fat mass and can increase plasma levels of triglycerides, lipids, and cholesterol independent of total caloric intake in both rats and humans, and weight gain from caloric overconsumption can be prevented by consuming smaller, more frequent meals in humans (14,18,20,21,35,55). These studies indicate that meal number and size can affect metabolism, but whether exposure to social stress alters the microstructure of food intake is unclear.…”

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confidence: 99%

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Meal patterns and hypothalamic NPY expression during chronic social stress and recovery

Melhorn

Krause²,

Scott

et al. 2010

American Journal of Physiology-Regulatory, Integrative and Comp

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In the present study, we examined meal patterns during and after exposure to the visible burrow system (VBS), a rodent model of chronic social stress, to determine how the microstructure of food intake relates to the metabolic consequences of social subordination. Male Long-Evans rats were housed in mixed-sex VBS colonies (4 male, 2 female) for 2 wk, during which time a dominance hierarchy formed [1 dominant male (DOM) and 3 subordinate males (SUB)], and then male rats were individually housed for a 3-wk recovery period. Controls were individually housed with females during the 2-wk VBS period and had no changes in ingestive behavior compared with a habituation period. During the hierarchy-formation phase of VBS housing, DOM and SUB had a reduced meal frequency, whereas SUB also had a reduced meal size. However, during the hierarchy-maintenance phase of VBS housing, DOM meal patterns did not differ from controls, whereas SUB continued to display a reduced food intake via less frequent meals. During recovery, DOM had comparable meal patterns to controls, whereas SUB had an increased meal size. Hypothalamic neuropeptide Y (NPY) mRNA levels were not different between these groups during the experimental period. Together, the results suggest that exposure to chronic social stress alters ingestive behavior both acutely and in the long term, which may influence the metabolic changes that accompany bouts of stress and recovery; however, these differences in meal patterns do not appear to be mediated by hypothalamic NPY.

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Section: Discussionmentioning

confidence: 92%

mentioning

confidence: 99%

Meal patterns and hypothalamic NPY expression during chronic social stress and recovery

Melhorn

Krause²,

Scott

et al. 2010

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Unlike the present study, little or no effect on food intake during relapse is observed with running wheel use. Interrupting this gorging meal pattern after calorie-restricted weight loss has been shown to affect weight regain, even when the total daily caloric food intake is standardized (45). Furthermore, proactively altering meal patterns can affect daily EI in humans (36).…”

Section: Discussionmentioning

confidence: 99%

Regular exercise attenuates the metabolic drive to regain weight after long-term weight loss

MacLean¹,

Higgins²,

Wyatt³

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

118

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Brown IE, Hill JO. Regular exercise attenuates the metabolic drive to regain weight after long-term weight loss. Am J Physiol Regul Integr Comp Physiol 297: R793-R802, 2009. First published July 8, 2009 doi:10.1152/ajpregu.00192.2009.-Weight loss is accompanied by several metabolic adaptations that work together to promote rapid, efficient regain. We employed a rodent model of regain to examine the effects of a regular bout of treadmill exercise on these adaptations. Obesity was induced in obesity-prone rats with 16 wk of high-fat feeding and limited physical activity. Obese rats were then weight reduced (ϳ14% of body wt) with a calorie-restricted, low-fat diet and maintained at that reduced weight for 8 wk by providing limited provisions of the diet with (EX) or without (SED) a daily bout of treadmill exercise (15 m/min, 30 min/day, 6 days/wk). Weight regain, energy balance, fuel utilization, adipocyte cellularity, and humoral signals of adiposity were monitored during eight subsequent weeks of ad libitum feeding while the rats maintained their respective regimens of physical activity. Regular exercise decreased the rate of regain early in relapse and lowered the defended body weight. During weight maintenance, regular exercise reduced the biological drive to eat so that it came closer to matching the suppressed level of energy expenditure. The diurnal extremes in fuel preference observed in weight-reduced rats were blunted, since exercise promoted the oxidation of fat during periods of feeding (dark cycle) and promoted the oxidation of carbohydrate (CHO) later in the day during periods of deprivation (light cycle) . At the end of relapse, exercise reestablished the homeostatic steady state between intake and expenditure to defend a lower body weight. Compared with SED rats, relapsed EX rats exhibited a reduced turnover of energy, a lower 24-h oxidation of CHO, fewer adipocytes in abdominal fat pads, and peripheral signals that overestimated their adiposity. These observations indicate that regimented exercise altered several metabolic adaptations to weight reduction in a manner that would coordinately attenuate the propensity to regain lost weight. fat oxidation; energy balance; indirect calorimetry; postobese; adipocyte cellularity WEIGHT REGAIN AFTER WEIGHT loss has been repeatedly shown in both obese animals (3, 4, 6, 9, 21-23, 25, 26, 30) and humans (14,18,32,42,43). A meta-analysis of a large number of U.S. weight loss studies summarized the propensity to regain after a wide variety of weight loss programs (1). Not only does lost weight tend to return, but the rate of return is highest immediately after the cessation of the structured weight loss program. Over 35% of the lost weight returns in the first year, and the majority is gained back within five years. Most people view their weight loss program as a transient change in their lifestyle and dietary habits or have difficulty in sustaining the changes that they have made to lose the weight (7, 11).The proposed reasons for the high rate of weight rega...

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“…Therefore, it may be speculated that energy expenditure decreased from the ®rst to the last weight cycle. However, there have been other weight cycling studies that have shown that rate of weight loss is not in¯uenced 5,8,11,14,15,17 or is actually increased 6 from the ®rst to last cycle.…”

Section: Rate Of Weight Lossmentioning

confidence: 99%

“…4,10,12,29 However, other studies have also shown that WC has either no effect on rates of weight gain and the ef®ciency of weight regain 5,11,22 or that these variables may even be decreased. 6,8,17,18 Reed et al 18 noted that differences in the results among WC studies arise in part due to the different methodologies that are utilized to produce WC. One important variable is whether WC occurred in obese or lean animals.…”

Section: Rate Of Weight Gain and Feeding Ef®ciencymentioning

confidence: 99%

Short-term weight cycling in aging female rats increases rate of weight gain but not body fat content

2000

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OBJECTIVE: To examine the effects of short-term repeated weight cycling (WC) above and below the baseline (BL) body weight (BW) on body weight regulation, feeding ef®ciency, and fat content in old female Wistar rats when dietary fat content was kept constant. DESIGN: Completely randomized. ANIMALS AND METHODS: Female Wistar rats, 11 months old at the beginning of the study, were randomly divided into six groups (12 per group) after a group of rats (BL) was sacri®ced for baseline data collection: the high fat gain (HFG) group gained weight to 20% above the BL weight with a high fat diet (HF) and returned to BL level by food restriction (50% of ad-libitum amount) for ®ve cycles; the high fat loss (HFL) group lost weight to 20% below the BL weight by food restriction (50% of ad-libitum amount) and regained to BL level by ad-libitum feeding for four cycles; the high fat ad-libitum (HFA) and low fat ad-libitum (LFA) groups were fed HF and low fat (LF) diet, respectively, adlibitum for the entire study; the high fat restricted (HFR group) and low fat restricted rats (LFR group) were fed the HF and LF diet, respectively, in restricted amounts to maintain BW at BL level. RESULTS: A trend of increased rates of weight gain and feeding ef®ciencies from the ®rst to last cycles for both WC groups was observed, and signi®cant increases was observed between cycles 4 and 5. The rate of weight gain and feeding ef®ciency of HFL was signi®cantly higher than that of the HFG group for all cycles (P`0.05). The rates of weight loss were signi®cantly decreasing with each successive cycle for HFG, but were unchanged for HFL. Percentage of body fat was not modi®ed permanently from BL to sacri®ce for both HFG and HFL groups. The body fat of HFA was higher than that of the other groups (P`0.01), while the body fat of LFA was signi®cantly higher than that of the LFR, BL and HFL groups (P`0.01), but was similar to that of the HFG and HFR groups. The body fat of WC groups and HFR were similar to each other. The percentage of internal fat (retroperitoneal omental) were similar for the WC groups. The percentage of internal fat of the HFG, HFR and LFA groups were similar, but were signi®cantly higher than that of the BL and LFR groups (P`0.05). The percentage of internal fat of HFA was signi®cantly higher than that of the rest of the groups (P`0.01). CONCLUSION: Short-term WC did not affect body fat content in these animals, but since weight gain became easier and weight loss became more dif®cult for animals in the HFG group, repeated WC may promote obesity in these rats. International Journal of Obesity (2000) 24, 236±245 Keywords: weight cycling; rates of weight gain and loss; feeding ef®ciency; body fat content Literature reviewObesity is a major health risk in the US, and it has been reported that approximately 33% of adults 20 y of age or older are overweight. 1 Many obese people who are dieting (women 50% and men 33%, 2 are able to lose weight initially, but because daily energy expenditure decreases dramatically, 3 weight maintenance at a...

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Weight cycling in female rats subjected to varying meal patterns

Cited by 8 publications

References 6 publications

Meal patterns and hypothalamic NPY expression during chronic social stress and recovery

Meal patterns and hypothalamic NPY expression during chronic social stress and recovery

Regular exercise attenuates the metabolic drive to regain weight after long-term weight loss

Short-term weight cycling in aging female rats increases rate of weight gain but not body fat content

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