Why NOT Losing Weight

Getting fitter and improving diet are very common New Year’s resolutions for many people and it is no surprise to find out that 48% of Brits vow to lose weight and over a third make a resolution to improve diet.

Some people and the likes of companies such as WW (side note, terrible branding!) would try and convince you that losing weight is simply calories in versus calories out. Yes, calories are one important factor, but there may be so many other factors such as hormonal issues, food allergies/intolerances, disrupted gut, heavy metal environmental toxicity, which are also at play.

Below are some of these little-known reasons I consider when I work with clients struggling to lose weight.

Food Allergies or Sensitivities

Most people with food allergies think that they know what they are allergic or sensitive to, however, the reality is unless you have a severe allergy (for example if you are allergic to peanuts or fish), you may notice food allergy or sensitivity, especially if you are consuming/being exposure to the food/allergen all the time (such as gluten in grains or casein/lactose in milk or dairy) regularly.

It is also important to note that you can develop an allergy/intolerance to a food (or something else, such as a mould allergy) at ANY POUNT IN YOUR LIFE. You don’t just develop allergies/intolerances as a child.

The symptoms of an allergy or sensitivity can be also very varying – migraines, sinusitis, rashes, low mood, stomach upset, feeling congested, joint pain, heart palpitations, keratosis (the ‘bumpy’ rash on the back of your arms) etc., so many people do not connect the dots so to speak.

The mechanism by which a food allergy or intolerance prevents you from losing weight is that the allergy/intolerance may create a low-grade inflammation in the body, which in turn affects your metabolism (the set of life-sustaining chemical reactions that happen in your body) and may also disrupt blood sugar regulation.

If I suspect that some of my clients might have an allergy or intolerance, I sometimes recommend functional testing or exclusion diets. Testing for Gluten Sensitivity for example is quite complicated, I have written a separate article about it here http://optimalhealthnutrition.co.uk/gluten-autoimmunity/.

Disrupted Gut and Microbiome

Scientists are beginning to understand more and more about the role of the bacteria in our guts and the role they play in immunity, mood, disease initiation, etc. Research (1), (2), (3) also links disrupted microbiome (the community of micro-organisms living together in out gut) to obesity.

One of the proposed mechanisms by which the microbiome influences weight is that some of the ‘bugs’ in our guts help us metabolise foods and utilise energy. Also, some of the ‘bad bugs’ and Candida overgrowth (type of yeast) might make us crave more sugar, whilst other bacteria such as Acetobacter and Lactobacillus species have been found to regulate appetite.

Factors that affect your microbial diversity (not an exclusive list) are birth delivery method (with vaginal delivery helping ‘inoculate’ the baby with the bacteria from the mother’s birth canal), breastfeeding, antibiotics ( including antibiotics coming from food consumption such as inorganic meat), lack of diversity in diet (‘good gut bugs’ like variety with suggestions that we should be consuming at least 40 different foods per day), food allergies/intolerances, chemical/toxic exposure, intestinal permeability or ‘leaky gut’, food additives, sugar, processed foods, alcohol consumption, etc.

As you can see some of these cannot be changed (such as birth delivery method), but a lot of them are lifestyle factors that can. The strategy in these cases is to adapt diet and lifestyle changes and sometimes even strain specific probiotic or pre-biotic ( foods that feed beneficial bacteria) interventions.

Heavy Metal Toxicity

Environmental toxins such as heavy metals ( such as aluminium, mercury, lead, arsenic) have also been linked to obesity and metabolic syndrome (4), (5). Further research in humans, however, due to the very toxic nature of heavy metals and ethical considerations is difficult to be carried out.

One of the suggested mechanisms of how heavy metal toxicity contributed to obesity is that environmental toxins such as heavy metals are often stored in fat cells, as our body’s protective mechanism. Sometimes, therefore, these hard to shift fat cells may be harbouring toxins, which our body tries to keep ‘safe’ especially if our detoxification pathways are not working optimally.

Heavy metals are, unfortunately, very common in everyday life, here are some of the main sources of the most common ones:

Mercury: Amalgam fillings, most fish, but particularly larger fish such as tuna and swordfish, thermometers, light bulbs, old paint, batteries, cigarette smoke, contaminated water/air, thimerosal (inorganic mercury) can also be found in vaccines, cosmetics, tattoo inks, eye drops and contact lens solutions as well as a disinfectant, some Ayurvedic herbs and other herbs/supplements often grown in China or India, etc.

Aluminum: foil, baking soda (and most commercially baked breads/cakes etc.), coffee pods, deodorants, heartburn medication (even over the counter ones), aluminum cookware, some Ayurvedic herbs and other herbs often grown in China or India, etc.

Arsenic: contaminated water/food, rice (including rice-based cereals and rice cakes), fish, shellfish, meat, poultry, dairy products, some Ayurvedic herbs and other herbs often grown in China or India, etc.

Lead: old paint, leaded pipes, leaded petrol, children’s jewellery and toys especially made in China (remember fidget spinners?), contaminated drinking water/air/soil, eating game (lead bullets), glazed dishes/cookware, hobbies such as stained-glass decorating/shooting, casting or soldering, some Ayurvedic herbs and other herbs often grown in China or India, etc.

If I suspect some of my clients have a heavy metal toxicity, there are specific functional medicine tests that can be carries out (such as urine challenge tests). The best intervention is prevention (such as stopping the use of aluminum foil in cooking for example) because chelation (the term means detox of heavy metals) can be very difficult and contra-indicated in some cases.

Optimising the detox pathways (such as Phase 1 and 2 of Liver Detox Pathways), supplementation of minerals such as Magnesium and Zinc (which get displaced by heavy metals) and increased antioxidant intake (Selenium, Glutathione, Vitamins E, C and A) may be a suitable intervention in such cases.

Hormonal Issues

First, let me start by saying (again) that hormones are relevant to men as well, hormonal issues are not just for the female part of the population.

Hormones such as Thyroid Hormones (your metabolism’s thermostat), Cortisol (the ‘stress’ hormone), Insulin (linked to blood sugar fluctuations and eating patters), Oestrogen (the primarily female hormone), Leptin (released by your fat cells) and Ghrelin (known as the hunger hormone) have all a part to play.

In fact, these are so important that I have written a separate article just relating to the issues around weight loss and these hormones, you can read it here.


  1. Davis CD. The gut microbiome and its role in obesity. Nutr Today. 2016;
  2. Barlow GM, Yu A, Mathur R. Role of the gut microbiome in obesity and diabetes mellitus. Nutrition in Clinical Practice. 2015.
  3. Chen J, He X, Huang J. Diet Effects in Gut Microbiome and Obesity. J Food Sci. 2014;
  4. Planchart A, Green A, Hoyo C, Mattingly CJ. Heavy Metal Exposure and Metabolic Syndrome: Evidence from Human and Model System Studies. Current environmental health reports. 2018.
  5. Padilla MA, Elobeid M, Ruden DM, Allison DB. An examination of the association of selected toxic metals with total and central obesity indices: NHANES 99-02. Int J Environ Res Public Health. 2010;