Metabolism: Everything You Need to Know

By: Claire Georgiou, Reboot Naturopath, B.HSc ND

Metabolism. It’s a popular word. It’s often believed to be “slow” if someone is struggling with weight loss, but a slow metabolism is rarely to blame. Dietary choices can have a supportive or destructive effect on your metabolism, the health of your hormones, liver and digestive system which all play a significant role in the way our body burns or stores fat.

What is metabolism?

The ‘metabolism’ is a set of life-sustaining chemical transformations within the cells. This is a complex biochemical process where calories in food and beverages are combined with oxygen to release the energy your body needs to function.

Even when you’re at rest, your body needs energy for all its life-sustaining functions, such as breathing, circulating blood, adjusting hormone levels, and growing and repairing cells. The number of calories your body uses to carry out these essential functions is known as your basal metabolic rate.

Several factors determine your individual basal metabolic rate, such as:

  • Your body size – the bigger you are the more calories you will burn to maintain essential functions in a resting state.
  • Muscle composition – the more muscle you have the higher your metabolic rate; muscle requires more energy for maintenance than fat cells.
  • Sex – men tend to have a higher muscle composition so they often have a higher metabolic rate.
  • Age – with aging, muscle tissue may decline and some metabolic functions may slow down with cellular age and hormonal changes.
  • Genetics – how efficient your ancestors burnt and maintained their energy reserves can have relevance in how you maintain and utilize your calories.
  • Some health conditions – some conditions can contribute to a slower metabolic rate such as hypothyroidism, Cushing’s syndrome, fatty liver infiltration, liver disease and other hormonal irregularities or changes.

Hormones and the Metabolism

Hormones can have a positive or negative impact on how we burn calories; excess estrogen levels tends to support increased fat storing while testosterone works towards burning fat and maintaining healthy muscle tissue. Elevated insulin as mentioned increases fat stores while glucagon works on burning fat. Thyroid hormones also influence the metabolism so an under-functioning thyroid will cause weight gain as the metabolism slows down and the person feels tired. Cortisol (stress hormone) increases fat stores and muscle breakdown. If you have a thyroid condition, you can learn more about our 60-Day Guided Reboot that is designed to specifically improve your health.

Dietary Choices: Help or Harm

Having high blood sugar, insulin resistance, hormonal imbalances, chronic stress and/or a fatty liver can cause our bodies to be in a chronic state of fat storing thus altering our metabolism. The hormones that tend to be elevated in this state of health increase cravings, appetite and inhibit our fat burning hormones.

Reboots are metabolically beneficial because they stop all processed unhealthy foods that offer NO nutritional content, providing only empty calories and are replaced with 100% plant-based foods that are highly nutrient dense. This helps to support and regulate healthier metabolic health, improved blood sugar control, liver detoxification support, improved hormonal health and better craving and appetite control.

Many plant-based Reboot foods boost the metabolism, such as:

  1. Chili
    Capsaicin has a thermogenic effect, this means it causes the body to burn extra calories for 20 minutes after you eat the peppers. Researchers are reporting new evidence that capsaicin, the stuff that gives chili peppers their fiery flavour, may help fight obesity by decreasing calorie intake, shrinking fat tissue and lowering fat levels in the blood.
  1. Ginger
    K. Han, a Japanese researcher, says ginger creates a boost in the metabolism. He led a study in which rats fed ginger extract lost weight while maintaining a high-fat diet.
  1. Grapefruit
    Grapefruit contains specialized antioxidants such as naringenin, that has shown to improve insulin sensitivity and help maintain a healthy weightStudies have demonstrated that consuming ½ a fresh grapefruit before each meal showed a significant reduction in the 2 hour post-glucose insulin levels compared with the placebo. This study also showed that the consumption of fresh grapefruit juice caused a 1.6 kg weight reduction over 12 weeks while the placebo group lost 0.3 kg.
  1. Lemons 
    Research has shown that serum insulin, glucose and leptin were significantly improved by lemon polyphenols, thereby improving insulin resistance and weight control. Lemons support liver health by improving the production of bile which supports the metabolism of fats in the diet. This is why so many people love to enjoy their warm lemon drink in the morning.
  1. Blueberries
    Researchers found that if the animals were given meals enriched with blueberries, they lost fat from their stomachs.
  1. Cabbage Family Vegetables
    These super vegetables also support the natural detoxification pathways through the liver which also supports weight loss. These vegetables support the second phase of liver detoxification which has an influence on the way we burn calories and store fat. See why the liver is our best fat burner!
  1. Protein
    Getting a healthy balance of protein from plant-based nutrition via nuts, seeds and legumes and from a healthy protein powder source like the Reboot with Joe Protein Powder is essential for the metabolism. Protein requires more energy to be utilized and metabolized and helps to support healthy blood sugar levels.
  1. Apple Cider Vinegar
    One study showed obese subjects were given 1 or 2 tbsp of ACV or placebo over a 12 week period. Results showed that 1 tbsp of ACV was associated with a loss of 2.6 lb while 2 tbsp per day was associated with 3.7 lb loss. Learn more on the benefits of ACV.

Other factors that can contribute to how many calories you burn daily:

As with most health and wellness advice, it is important to keep hydrated to avoid a metabolic drop. With slight dehydration our metabolism may slow slightly to reduce cellular hydration loss. In one small study they found that drinking 16 oz (500 ml) of water had a 30% increase in caloric burn for 10-40 minutes afterwards. So as you can imagine keeping that water intake up throughout the day can have a significant effect on weight control.

Exercise, activity levels, stress and sleep all have an impact on our metabolism. Exercise and moving your body certainly supports more calories being burnt.  Cardio such as cycling, walking and running are important along with strength training such as weight lifting, Pilates and yoga to enhance your muscle tone to increase your caloric burn.

Physical activity of any nature increases calories being burnt including walking up the stairs rather than taking the elevator, standing rather than sitting or getting off the train or bus 1 stop earlier. It all makes a difference when it’s consistent.

These all have a small effect on our metabolic rate but consistency with high nutrient foods,  activity and improved lifestyle factors adds up and will support a highly functioning healthy metabolism.


Claire Georgiou, Reboot Naturopath, B.HSc ND

Claire Georgiou is an Australian Naturopath, Nutritionist and Herbalist who has completed a Bachelor of Health Science (Compl. Medicine) and an Advanced Diploma of Nutrition, Naturopathy and Herbal Medicine. She has more than 14 years of clinical experience specializing in liver disease, autoimmune disease, thyroid conditions, diabetes, insulin resistance, digestive disorders, chronic infections, children’s health, fertility and pregnancy care. Claire consults in private practice in Sydney and also offers consults out of area and is an accredited member of the Australian Traditional Medicine Society. Claire has worked closely for many years with Dr. Sandra Cabot, who is known as the “Liver Cleansing Doctor” and has written more than 25 health related books. Claire writes health related articles, creates healthy recipes and is one of the nutritionists who runs our Guided Reboot programs.

More posts from