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Why Under-Eating Can Cause You to Retain Weight

f you’ve been trying to shed some pounds but find yourself stuck at a plateau, the culprit might be something unexpected: under-eating. While it might seem counterintuitive, consuming too few calories can actually cause your body to hold onto weight. In this post, we’ll explore why under-eating can sabotage your weight loss efforts, supported by relevant studies and statistics.

1. The Science Behind Metabolic Slowdown

When you drastically cut your calorie intake, your body goes into survival mode. This is a natural response that dates back to our ancestors, who needed to survive periods of food scarcity. According to a study published in the journal “Metabolism,” when the body senses a significant decrease in calorie intake, it reduces the basal metabolic rate (BMR) to conserve energy. This means you burn fewer calories at rest, making it harder to lose weight.

In fact, the Biggest Loser study found that participants who drastically reduced their calorie intake experienced a substantial slowdown in their metabolism, which persisted even after they returned to a more normal diet. This metabolic adaptation can make long-term weight loss incredibly challenging.

2. Hormonal Imbalances and Weight Retention

Under-eating can also disrupt your hormones, particularly those involved in hunger and satiety. Leptin, a hormone that helps regulate appetite and fat storage, decreases with severe calorie restriction. Low leptin levels signal the body to conserve energy and increase hunger, leading to potential overeating once normal eating resumes.

A study in the “Journal of Clinical Endocrinology and Metabolism” highlighted that prolonged calorie restriction leads to lower leptin levels, increased hunger, and decreased energy expenditure. This hormonal imbalance can create a vicious cycle, making it harder to stick to a healthy diet and maintain weight loss.

3. The Impact of Muscle Loss

When you under-eat, especially if you’re not consuming enough protein, your body may start to break down muscle tissue for energy. Muscle mass is metabolically active, meaning it burns more calories than fat even at rest. Losing muscle can therefore further decrease your metabolic rate, making weight loss even more difficult.

A study published in “The American Journal of Clinical Nutrition” found that individuals on a very low-calorie diet lost a significant amount of muscle mass, which contributed to a lower metabolic rate. Maintaining muscle mass through adequate nutrition and resistance training is crucial for sustainable weight loss.

Optimizing Your Weight Loss Journey in Kamloops

For residents of Kamloops seeking effective weight loss solutions, personal training can play a pivotal role. At JR Training Systems, our programs are designed to avoid the pitfalls of under-eating while promoting healthy, sustainable weight loss. Whether you’re interested in our Fit Over 50 program, 30 Days Results in Advance, or our newly launched Semi-Private Training Program, we tailor our approach to meet your individual needs.

Our personal training sessions incorporate balanced nutrition plans that ensure you’re not undereating, but fueling your body properly to support weight loss, muscle retention, and overall well-being. By focusing on holistic health, we help you achieve your fitness goals without the setbacks associated with severe calorie restriction.


Under-eating can counterintuitively lead to weight retention due to metabolic slowdown, hormonal imbalances, and muscle loss. By understanding these mechanisms and adopting a balanced approach to nutrition and exercise, you can achieve sustainable weight loss. For those in Kamloops looking to transform their health and fitness, personal training with JR Training Systems offers a tailored, supportive, and effective pathway to your goals.

Optimize your weight loss journey today by avoiding the pitfalls of under-eating and embracing a holistic approach with the guidance of professional personal training. Contact us to learn more about our programs and start your journey towards a healthier you.

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