Menstrual Cycle and Weight

While there may be minor changes in metabolism, food intake and cravings throughout the menstrual cycle in addition to possible water retention, this will not impact weight loss success.
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Food Intake and Metabolism
While overeating is the popular perception, the research has shown that there are minor changes in actual food intake throughout the menstrual cycle. Most studies suggest an increase in eating of around 100 to 200 calories in the days before bleeding occurs, 1,2 but this appears to be offset by the small rise in metabolism (around 5 to 10%) 3 that occurs during the same time period. In other words, the body tends to adjust the calories in/calories out on its own. Therefore, in a weight stable state, no changes in weight will occur. However, if actively losing weight by following a restricted-calorie food plan, the likely result would be a slight (but hardly noticeable) increase in weight loss due to the increased metabolism without the usual increase in calories. Alternatively, the result instead could be a slightly greater difficulty in following the food plan because of increased hunger during that period.

Food Cravings
Although food cravings are commonly reported during certain times of the menstrual cycle, the scientific evidence on the subjects is limited. Some smaller studies suggest a link, particularly a craving for high carbohydrate sweets. 4,5 These studies also show that cravings tend to occur more often in women with premenstrual syndrome (PMS) and that the cravings increase as symptoms worsen. 6 While more research is needed to understand food cravings, the good news is that they do not appear to translate into large increases in calorie intake and subsequent weight gain.

Water Retention
The most likely reason for a weight gain is water retention. While this is a common symptom that can be particularly discouraging when following a structured food plan, 7 the weight gain is usually minor and temporary (that is, any weight that is gained is lost around the time of menstruation). Furthermore, water retention can be lessened during this time period by making small dietary changes, like reducing sodium and increasing fluids.

Bottom Line: Major fluctuations in eating and weight during certain periods of the menstrual cycle are a common perception, but studies done in the area find that the changes are minor, temporary and will not impact on weight loss success.

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FOOTNOTES

1 Buffenstein R et al. Food intake and the menstrual cycle: a retrospective analysis, with implications for appetite research. Physiol Behav. 1995 Dec;58(6):1067-77.

2 Johnson WG et al. Energy regulation over the menstrual cycle. Physiol Behav. 1994 Sep;56(3):523-27.

3 Bisdee JT et l. Changes in energy expenditure during the menstrual cycle . Br J Nutr. 1989 Mar;61(2):187-99.

4 Dye L & Blundell JE. Menstrual cycle and appetite control: implications for weight regulation . Human Reprod. 1997 June;12(6):1142-51.

5 Bryant M et al. Modest changes in dietary intake across the menstrual cycle: implications for food intake research . Br J Nutr. 2006 Nov;96(5):888-94.

6 Both-Orthman et al. Menstrual cycle phase-related changes in appetite in patients with premenstrual syndrome and in control subjects . Am J Psychiatry. 1988 May;145(5):628-31.

7 Ross C, Coleman G & Stojanovska C. Prospectively reported symptom change across the menstrual cycle in users and non-users of oral contraceptives . J Psychosom Obstet Gynaecol. 2003 Mar;24(1):15-29.