Randomized evaluation of a low fat ad libitum carbohydrate diet for weight reduction.

Restricting dietary fat intake while consuming carbohydrates ad libitum has recently been promoted as a weight loss regimen. Sixty subjects (52 females and eight males) were randomized to low fat ad libitum carbohydrate (low-fat) or low fat with caloric restriction (low-calorie) behaviour modification treatments. Forty-nine subjects completed the 16-20 week programme. Subjects in both groups reported averaging over five exercise sessions per week during treatment. The low-calorie group lost significantly more weight (males 11.8 kg, s.d. 6.4; females 8.2 kg, s.d. 4.2) than the low-fat group (males 8.0 kg, s.d. 1.3; females 3.9 kg, s.d. 3.7). Both groups of subjects lost similar amounts of lean body mass. There was significantly greater loss of body fat in the low-calorie group. A slight reduction in RMR, adjusted for changes in lean body mass, was observed in both groups. Fat intake was reduced from 90 to 30 g per day. Subjects in both groups reduced their total energy intake with the low-calorie group consuming fewer calories per day than the low-fat group. Both groups showed significant and equivalent improvements in eating habits based on microanalysis of eating diaries. Eating in social situations and emotional eating, however, continued to cause adherence problems during treatment for both groups. Follow-up data collected 9-12 months after completion of treatment on 65% of the subjects completing the study showed no significant difference between the two groups in weight losses from baseline (low-fat group 2.6 kg; low-calorie group 5.5 kg).

A sequential behavioral analysis of craving sweets in obese women.

This study compared 40 female participants in a behavioral weight loss program who frequently reported craving sweets to 40 who rarely reported craving sweets using 2-week behavioral eating diaries. The two groups were compared on physiological, demographic, and questionnaire measures and no significant differences were found. There were no significant differences in macronutrient intake either overall or in a wide range of specific situations. The relative proportions of carbohydrate, protein, and fat consumed in association with craving sweets differed only slightly from the composition of other meals and snacks. Carbohydrate and protein intake when craving sweets was similar to breakfasts while the relative amount of fat consumed when craving sweets was comparable to episodes of overeating. The two groups differed in their reporting of moods with the high-craving group reporting more boredom and less stress than the low-craving group. The relationship between situational and mood variables and reports of craving sweets did not differ between the two groups. Craving sweets was negatively associated with hunger and was not associated with meal skipping. A sequential analysis demonstrated that eating in response to craving sweets triggers an abstinence violation effect. These data are not consistent with the hypothesis that sweet craver's consume high-carbohydrate, low-protein meals and snacks in order to self-medicate depression caused by serotonin depletion. Instead, the data suggest that we should further explore the role of food palatability and food-related cognitions in order to understand craving sweets.

Physiological effects of dieting and bingeing in rats.

Female rats were assigned to dietary conditions as follows for 3.5 months: 1) Low-fat control (LFC); 2) Moderately high-fat control (HFC); 3) Alternation between restricted access to a low-fat diet and ad lib access to a very high fat diet (RA); 4) Unrestricted access to the same diets as RA (URA). Results indicate that: 1) HFC consumed the same energy as LFC, but showed a tendency to become heavier and fatter through greater food efficiency. 2) URA and LFC did not differ in body weight, food intake, body composition or energy efficiency. 3) Intake of the very high fat diet declined over time in the RA. 4) RA ate less total calories, weighed less than all other groups, and showed a tendency for decreased percentage body fat and increased percentage of weight gained due to FFM gained. Results provide no evidence that dieting and bingeing promote obesity or increased preference for dietary fat, and suggest that dietary restriction has greater impact on energy balance and body composition than does alternation of diet composition.

The influence of family support on chronic pain.

This study examined the role family support plays in insulating chronic pain patients from maladaptive behaviors associated with their pain. Two hundred and thirty-three patients who described their family as always being supportive and never having any conflicts were compared with 275 chronic pain patients who endorsed having family disharmony and limited support. One year after completing an out-patient pain program a random sample of 181 of these patients were followed to determine the extent to which family support influenced treatment outcome. The patients who reported having non-supportive families tended to have liability and work-related injuries, relied on medication, reported having more pain sites and used more pain descriptors in describing their pain. These patients also tended to show more pain behaviors and more emotional distress compared with pain patients coming from supportive families. On follow-up, patients who described their families as being supportive reported significantly less pain intensity, less reliance on medication and greater activity levels. They tended to be working and not to have gone elsewhere for treatment of their pain compared with patients who described their family as non-supportive. The results of this study demonstrate that perceived support is an important factor in the rehabilitation of chronic pain patients.