Understanding Metabolism and its role in weight loss

Updated on May 6, 2026

Metabolism is the rate at which the body burns calories, essential for weight loss. It converts food and drink into energy and can be influenced by factors like stress, exercise, gender, age, and health conditions such as hypothyroidism. A higher metabolism aids weight loss, but losing weight can slow it down, making maintenance difficult.

Over-exercising may cause stress and disrupt metabolism. Basal metabolic rate (BMR) accounts for most calorie burning. While some foods and hydration can slightly boost metabolism, the effects are minimal. Understanding your body's needs is crucial; prioritize a balanced approach over fad diets.

Metabolism, or more specifically, metabolic rate, is the rate at which your body burns calories.

This is what matters when it comes to weight loss. But do you actually know how metabolism works?

Metabolism is a process

Metabolism is a chemical process that converts the energy from the food we eat and the drinks we consume into the fuel our body needs ^[1]. Factors that can affect this process include stress, excessive exercise, and even weight loss!

Metabolism also varies between people, by gender, and with age. Health conditions such as hypothyroidism can also affect your metabolism ^[2].

Metabolism and weight loss

The higher your metabolism, the more calories you burn, and you’ll lose weight. But when you lose weight, your metabolism is affected ^[3].

Why is that? Weight loss slows your metabolism, making it harder to stave off weight gain. Strange and even cruel, but alas, it’s true.

On that note, crash dieting is a big no-no!

More exercise, fewer results

There is no doubting the benefits of physical activities such as exercise, but if you’re thinking of amping up your routine, think again.

Too much exercise can cause the body to enter a state of inflammation and stress ^[4].

When this happens, your hormones go into chaos, which will mess with your metabolism.

Rest is essential for the body to recover, and a balanced workout is equally important.

Feel the burn

Successful weight loss is down to your basal metabolism, meaning the energy needed to keep you functioning ^[5].

It’s not to be confused with the energy you need during physical activity.

Basal metabolic rate (BMR) accounts for the bulk of the calories the body burns, surpassing physical activity by a wide margin!

The body’s resting metabolic rate (RMR), which is when your body is at rest, is also decisive to an extent when it comes to weight loss.

Speeding up metabolism

While coffee, chilli and other spices may speed up your body’s basal metabolic rate ^[6], the improvement is insignificant and limited, making them ineffective.

In particular, proteins like chicken ^[7] and fish ^[8] may increase metabolism when consumed in small amounts throughout the day.

Hydration also helps, and drinking sufficient water aids the body in metabolising food ^[9] and preventing overeating ^[10].

The science behind weight loss can be a real challenge to understand, with the various research and studies involved, but don’t let that intimidate you.

When it comes to metabolism and weight loss, always remember not to rush into any fads.

The key is always to know your body and what it needs to achieve your goal.

Do fad diets affect metabolism?

There are many diets, including low-fat, low-carb, and even special diets focused on eating patterns like DASH, Mediterranean, Intermittent Energy Restriction, Paleo, and many others.

“However,” explains Dr Ivan Puah, “studies have failed to prove the long-term superiority of one diet over another.”

Fad diets slow down metabolism, as extreme calorie restriction or restrictive eating will lead the body into starvation mode. Those on such diets may notice loss of muscle mass, weight re-gain, slower calorie burning, weak bodies and foggy brains.

If you need assistance losing weight healthily, the Amaris B. Weight Loss programme is worth considering. Our doctor-led, tailored weight loss plan includes a nutrition guide, an exercise schedule, GLP-1 medication (oral or injectable), medical monitoring, doctor consultations and follow-up, and a progress monitor.

Make an appointment with Dr Ivan Puah today for a private consultation.

FAQ

What happens when we lose weight?

Our bodies have fat cells that store excess energy for survival. Normally, the body keeps our weight stable, just as it controls temperature and blood pressure. When we lose weight, those fat cells shrink in size, but they don't disappear.

How much weight can you lose on GLP-1 medication?

Most people lose around 2% of their body weight. However, note that this rate can vary depending on your initial weight, workout habits, dietary changes, and metabolism ^[11].

What to expect after the first GLP-1 medication?

The first week after your initial intake is an important adjustment period as your body begins responding to the medication. You may experience changes in appetite, mild digestive symptoms, or gradual shifts in energy levels ^[12].

What should I avoid while taking GLP-1 medication?

In general, it is recommended to eat healthily and limit fatty, sugary foods, alcohol, fizzy drinks, fried foods, pastries, creamy sauces, and processed meats. However, we suggest avoiding spicy foods while on GLP-1.

Reference

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2. Shaji, B., & Joel, J. J. (2022). Impact of Hypothyroidism on Metabolic and Cognitive Dysfunction: A Comprehensive Review. Journal of Young Pharmacists, 14(4).
3. Safe, I. C. Improve your metabolism for overall health (February 2020).
4. Magherini, F., Fiaschi, T., Marzocchini, R., Mannelli, M., Gamberi, T., Modesti, P. A., & Modesti, A. (2019). Oxidative stress in exercise training: The involvement of inflammation and peripheral signals. Free radical research, 53(11-12), 1155-1165.
5. Soares, M. J., Cummings, N. K., & Ping-Delfos, W. L. C. S. (2011). Energy metabolism and the metabolic syndrome: does a lower basal metabolic rate signal recovery following weight loss?. Diabetes & Metabolic Syndrome: Clinical Research & Reviews, 5(2), 98-101.
6. Westerterp-Plantenga, M., Diepvens, K., Joosen, A. M., Bérubé-Parent, S., & Tremblay, A. (2006). Metabolic effects of spices, teas, and caffeine. Physiology & behavior, 89(1), 85-91.
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8. Mendivil CO. Fish Consumption: A Review of Its Effects on Metabolic and Hormonal Health. Nutr Metab Insights. 2021 Jun 3;14:11786388211022378. doi: 10.1177/11786388211022378. PMID: 34158802; PMCID: PMC8182174.
9. Rani, J., Sharma, U. K., & Sharma, D. N. (2018). Role of adequate water intake in purification of body. Environment Conservation Journal, 19(1&2), 183-186.
10. McKay NJ, Belous IV, Temple JL. Increasing water intake influences hunger and food preference, but does not reliably suppress energy intake in adults. Physiol Behav. 2018 Oct 1;194:15-22. doi: 10.1016/j.physbeh.2018.04.024. Epub 2018 Apr 17. PMID: 29678599.
11. Reiss AB, Gulkarov S, Lau R, Klek SP, Srivastava A, Renna HA, De Leon J. Weight Reduction with GLP-1 Agonists and Paths for Discontinuation While Maintaining Weight Loss. Biomolecules. 2025 Mar 13;15(3):408. doi: 10.3390/biom15030408. PMID: 40149944; PMCID: PMC11940170.
12. Bettadapura S, Dowling K, Jablon K, Al-Humadi AW, le Roux CW. Changes in food preferences and ingestive behaviors after glucagon-like peptide-1 analog treatment: techniques and opportunities. Int J Obes (Lond). 2025 Mar;49(3):418-426. doi: 10.1038/s41366-024-01500-y. Epub 2024 Mar 7. PMID: 38454010; PMCID: PMC11971042.