Evaluation of the Association Between the Menstrual Cycle and Weight Loss in Healthy, Overweight Premenopausal Women
Evaluation of the Association Between the Menstrual Cycle and Weight Loss in Healthy, Overweight Premenopausal Women
Achievement and maintenance of weight loss in obese individuals has proven difficult. Many
 hypotheses have suggested potential biological mechanisms to explain why weight loss attempts
 often fail, and the surrounding obesogenic environment also seems an obvious candidate. Among
 the biological factors proposed is gender, and weight loss trials have frequently shown that
 females are less successful than males at losing weight and at maintaining weight loss.

 Women's weight is influenced by the menstrual cycle, in which changes in hormonal levels and
 interactions work to modulate fertility. These hormones control the menstrual cycle and
 coordinate the required changes in energy intake, expenditure, and storage, whilst preparing
 the body for pregnancy every month. As reproduction is a primary biological function, these
 hormones may be such strong mediators of eating behavior that they influence the outcome of a
 weight loss attempt. The menstrual cycle should therefore be taken into consideration as a
 factor in the physiology of energy balance in premenopausal women.

 The cycle can be divided into three phases: menstruation or early follicular phase (days
 1-5), late follicular phase that lasts until ovulation (~days 6-14, and the luteal phase
 (days 15-28).

 Studies have shown that in the luteal phase of the menstrual cycle, women's energy intake and
 energy expenditure are increased and women experience more frequent cravings for foods,
 particularly those high in carbohydrate and fat, than during the follicular phase. A trend
 towards reduced carbohydrate utilization and increased fat oxidation in the luteal phase has
 also been reported, together with prolonged time to exhaustion when exercising at submaximal
 intensities. This suggests that the potential of the underlying physiology related to each
 phase of the menstrual cycle may be worth considering as an element in strategies to optimize
 weight loss.

 In 2010 the investigators carried out a 90-day randomized, controlled pilot study in order to
 gain feedback on and assess acceptance of the meal and exercise plans being used and to
 observe if less control visits than planed in the main study were sufficient to achieve good
 compliance. Twenty eight were sreened and 24 were included. Subjects were randomized to
 either program A (given meal and exercise plans in relation to phases of their menstrual
 cycles) or Program B (a reduced calorie diet, calorie-matched to program A). The pilot study
 showed that Group A (The Menstralean group) tended to have a greater average weight loss at
 60 days (-5.29 vs -3.57 kg, p = 0.06) and 90 days (-4.22 vs -2.75 kgs, p = 0.2) compared to
 the control groups. There was a dropout rate of 27%. This was primarily due to an inadequate
 number of control visits and contact with the subjects. Thus the Menstralean program seems to
 have the potential to enhance weight loss in overweight and obese women. However, the main
 study has to be carried out with more subjects in each group in a longer duration and with
 more support and contact with the subjects.

 The aim of the present trial is to examine the impact of the menstrual cycle on weight loss
 attempts in healthy overweight (BMI > 27 kg/m2) premenopausal women (18-40 years) randomized
 to two different weight management programs for a period of 6 months.
Inclusion Criteria:

 -  Healthy females between the ages of 18-40 (inclusive)

 -  BMI > 27 kg/m².

 -  Regular menstrual cycle (28 ± 4 days - with a maximum of 4 days within-subject
 variation in menstrual cycle duration.

 -  Weight stable (within ± 3-kg) 2 months prior to study inclusion

 -  Must use barrier contraception (e.g. male/female condom) for the study's duration

 -  Must be willing to follow the prescribed diet/exercise plan for the study's duration

 Exclusion Criteria:

 -  On hormonal contraceptives (IUD are allowed) or any other daily use of medications
 which can make the subject unsuitable for inclusion in the study.

 -  Any significant health problem (history of cancer, HIV/AIDS, Diabetes, cardiovascular
 disease, untreated hypothyroidism, etc.)

 -  Restrictions against participating in cardiovascular exercise and strength training

 -  Any condition, which in the opinion of the investigator makes the subject unsuitable
 for inclusion in the study.

 -  Women who are pregnant,lactating, or planning to become pregnant during the study
 period