What are the causes of weight loss plateaus?

From the Guidelines

Weight loss plateaus are primarily caused by the body's adaptation to the current diet and exercise routine, leading to a decrease in metabolism and a subsequent stall in weight loss. This phenomenon is a normal physiological response as the body tries to maintain homeostasis. To overcome a plateau, it is essential to reassess and adjust the current lifestyle intervention. According to the 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults 1, a comprehensive lifestyle intervention that includes dietary changes, increased physical activity, and behavioral modifications can produce clinically meaningful health benefits, even with modest weight loss of 3%–5%.

Some key factors that contribute to weight loss plateaus include:

• Insufficient caloric deficit: as the body adapts to the current diet, the caloric needs may decrease, requiring a recalculation of the daily caloric intake 1.
• Inadequate protein intake: failing to consume enough protein (0.7-1g per pound of body weight) can lead to muscle loss, which in turn slows down metabolism.
• Poor sleep quality and chronic stress: these factors can elevate cortisol levels, promoting fat storage and hindering weight loss efforts.
• Lack of variety in exercise routine: muscles become efficient at familiar movements, making it essential to increase exercise intensity or try new activities to challenge the body differently.

To overcome a weight loss plateau, consider the following strategies:

• Adjust caloric intake based on the patient's preferences and health status, and preferably refer to a nutrition professional for counseling 1.
• Incorporate strength training 2-3 times weekly to build metabolism-boosting muscle.
• Prioritize quality sleep (7-9 hours nightly) and stress management techniques, such as meditation or yoga.
• Consider intermittent fasting or cycling calorie intake between lower and higher days to prevent metabolic adaptation.

From the FDA Drug Label

The rate of weight loss is greatest in the first weeks of therapy for both drug and placebo subjects and tends to decrease in succeeding weeks. The causes of weight loss plateaus are not established, but it is observed that the rate of weight loss tends to decrease over time.

• The initial weight loss is greater, but it slows down in succeeding weeks. The FDA drug label does not provide a direct answer to the causes of weight loss plateaus, but it mentions that the weight loss is affected by variables other than the drugs prescribed, such as the physician-investigator, the population treated, and the diet prescribed 2.

From the Research

Metabolic Adaptations

• Metabolic adaptations occur with weight loss, resulting in increased hunger and reduced energy requirements, producing an "energy gap" where more energy is desired than required 3
• These adaptations include a decrease in circulating leptin and resting metabolic rate (RMR), decreased thermic effect of food (TEF), and increased energy efficiency at work intensities characteristic of activities of daily living 3
• Metabolic adaptation can lead to weight regain, and individuals who achieve predicted weight loss targets after a low-calorie diet are characterized by reduced metabolic adaptation 4

Hormonal Changes

• The increased hunger associated with weight loss is linked to elevation of the orexigenic hormone ghrelin and decrements in anorexigenic hormones 3
• Physiological adaptations to weight loss also include perturbations in the levels of circulating appetite-related hormones and energy homeostasis 5

Dietary Factors

• Less hunger and greater satiation have been associated with higher intakes of protein and dietary fiber, and lower glycemic load diets 3
• An intermittent lack of diet adherence, rather than metabolic adaptation, is a major contributor to the frequently observed early weight-loss plateau 6

Physical Activity

• High levels of physical activity are characteristic of most successful weight maintainers 3
• Regular exercise can attenuate the metabolic drive to regain weight after long-term weight loss, and promote the oxidation of fat during periods of feeding and carbohydrate during periods of deprivation 7
• Exercise can also reestablish the homeostatic steady state between intake and expenditure to defend a lower body weight 7