Slow metabolism and GLP-1s: what’s normal and how to support It

Metabolism is the process by which your body converts what you eat and drink into energy.

A slow metabolism can impact your overall health, energy levels, and weight.

Understanding the symptoms of a slow metabolism can help you identify issues early and take steps to improve your metabolic health.

 

What is metabolism?

Metabolism involves all the chemical reactions in your body that keep you alive and functioning. These reactions include breaking down nutrients from food, converting those nutrients into energy, and building and repairing tissues.

Basal Metabolic Rate (BMR)

BMR is the number of calories your body needs to maintain basic physiological functions at rest, such as breathing, circulation, and cell production. BMR accounts for about 60-75% of your total daily energy expenditure.

Factors affecting metabolism

• Age. Metabolism tends to slow down with age.
• Gender. Men generally have a higher BMR than women due to having more muscle mass.
• Muscle. More muscle mass means a higher BMR.
• Hormones. Thyroid hormones, insulin, and other hormones play significant roles in regulating metabolism.
• Genetics. Your genetic makeup can influence your metabolic rate.

Weight gain

One of the most noticeable symptoms of a slow metabolism is unexplained weight gain or difficulty losing weight despite regular exercise and a healthy diet. This occurs because your body burns fewer calories at rest and during physical activity.

Fatigue

Persistent tiredness or low energy levels can indicate a slow metabolism. Your body may struggle to convert food into energy efficiently, leading to feelings of fatigue.

Cold intolerance

Feeling unusually cold, especially in the hands and feet, can be a sign of a slow metabolism. This happens because your body is not generating enough heat through metabolic processes.

Dry skin and hair

A slow metabolism can lead to dry, brittle hair and skin. This is due to decreased circulation and a slower rate of cell turnover and repair.

Constipation

Slowed digestion is a common symptom of a slow metabolism. This can result in infrequent bowel movements and constipation.

Muscle weakness

A slow metabolism can cause muscle weakness or a feeling of heaviness in the limbs. This is often due to decreased muscle mass and energy production.

Hair loss

Significant hair loss or thinning can be associated with a slow metabolism. This is often related to hormonal imbalances that affect hair growth cycles.

1. Hypothyroidism. Hypothyroidism, or an underactive thyroid, is a common cause of slow metabolism. The thyroid gland produces hormones that regulate metabolism, and insufficient thyroid hormone levels can slow metabolic processes.
2. Hormonal imbalances. Imbalances in hormones such as insulin and cortisol can affect metabolic rate. For example, high cortisol levels from chronic stress can lead to weight gain and metabolic slowdowns.
3. Nutrient deficiencies. Deficiencies in essential nutrients such as iron, iodine, and vitamin D can impair metabolic function. These nutrients play crucial roles in energy production and thyroid function.
4. Lack of physical activity. A sedentary lifestyle can lead to muscle loss and a slower metabolism. Regular physical activity helps maintain muscle mass and boost metabolic rate.
5. Poor diet. Diets high in processed foods, sugars, and unhealthy fats can negatively impact metabolism. Conversely, a balanced diet with adequate protein, healthy fats, and complex carbohydrates supports metabolic health.
6. Ageing. As you age, you naturally lose muscle mass and experience hormonal changes that can slow down metabolism. Maintaining an active lifestyle and balanced diet can mitigate some of these effects.
7. Chronic stress. Chronic stress and elevated cortisol levels can disrupt metabolic processes and lead to weight gain, particularly around the abdomen.
8. Genetics. Your genetic makeup can influence your metabolic rate and predisposition to certain metabolic disorders.

GLP-1 receptor agonists help the body regulate blood sugar, slow digestion, and reduce appetite, all of which can temporarily lower energy expenditure because you’re eating fewer calories.

However, this doesn’t mean your metabolism is permanently slower. In fact, as you lose weight and improve insulin sensitivity, your metabolism becomes more efficient. The key is maintaining enough muscle, nutrients, and hydration to keep energy levels steady.

Supporting your metabolism on GLP-1s helps to:

• Preserve muscle and prevent fatigue
• Maintain long-term weight management
• Avoid dips in mood or motivation
• Encourage sustainable results beyond treatment 

Increase physical activity

Engage in regular cardiovascular exercise, such as running, cycling, or swimming, to burn calories and improve your cardiovascular health. Incorporate strength training exercises to build and maintain muscle mass, which increases BMR.

Eat a regular, balanced diet

Eat a diet rich in whole foods, including lean proteins, healthy fats, and complex carbohydrates. Include metabolism-boosting foods like green tea, chilli peppers, and high-protein foods. Avoid highly processed foods, sugary snacks, and excessive alcohol consumption.

Prioritise protein

Protein helps preserve lean muscle, which supports your metabolic rate. Include it at every meal: eggs, yoghurt, fish, tofu, or protein powder all work well. See High-Protein Eating on GLP-1s.

Stay hydrated

Drinking plenty of water supports metabolic processes and overall health. Aim for at least 8 cups (2 litres) of water daily.

Get enough sleep

Prioritise quality sleep to support metabolic function and overall wellbeing. Aim for 7-9 hours of sleep per night.

Manage stress

Practice stress-reducing techniques such as yoga, meditation, deep breathing exercises, or spending time in nature.

Eat small, frequent meals

Eating small, balanced meals throughout the day can help keep your metabolism active and prevent large fluctuations in blood sugar levels.

Optimise thyroid function

Ensure you consume enough iodine-rich foods, such as fish, dairy, and seaweed, to support your thyroid health. If you suspect hypothyroidism, seek medical advice for a proper diagnosis and treatment.

Speak to a Medicspot clinician if you:

• Experience persistent fatigue or dizziness
• Have ongoing digestive discomfort
• See a sudden slowdown in progress or energy levels
• Want tailored advice on exercise or nutrition for metabolism support

Medicspot’s clinical team can help review your medication, meal pattern, and overall energy balance to ensure you’re supported safely.

Medicspot’s clinicians and nutrition experts guide GLP-1 users through every stage of their treatment. From managing appetite and energy to preserving muscle and metabolism, our experts help you stay healthy and motivated as your body adjusts.

Take our free online assessment to see if GLP-1 treatment could be right for you, or use the weight loss calculator below to find out instantly if you are likely to be eligible and to see how much weight you could lose.

• A slight drop in calorie burn is normal during GLP-1 treatment.
• Focus on protein, hydration, and gentle activity to maintain metabolism.
• Eat regular, small meals and avoid skipping food.
• Prioritise sleep and self-care to keep energy steady.
• Seek support if low energy persists or affects daily life.

Disclaimer

This article is for general information only and should not be used for the diagnosis or treatment of medical conditions. Medic Spot Limited has used all reasonable care in compiling the information but makes no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. In the event of an emergency, please call 999 for immediate assistance.

There is no guarantee of a specific weight loss medication being prescribed. Clinicians will review your online questionnaire and will recommend the most appropriate weight loss treatments for you based on your answers. In some cases the clinicians may contact you for additional information. See our Terms of Service for more information.