5 min|Rhiannon Lockhart

Why Weight Loss Isn't Only About Calories

Nutrition, Gut Health, Hormones

Have you been told that the reason you can’t lose weight is because you consume more calories than you expend? Well, it’s time to break that stigma: weight loss isn’t only about calories.

Okay, yes. Calories most definitely play a role in weight loss, but only up to a certain point. Consuming excess calories on a regular basis without expending enough energy is still a surefire way to increase weight. However, if you feel like you’ve been on a diet rollercoaster for years with little to no success, it’s time to dig deeper.

Food Sensitivities

Both food sensitivities and food allergies can impact weight gain.

A food allergy is an immunologic response. This means that when you eat something you are allergic to, your immune system jumps into action to protect you and prompts an allergic response - anaphylaxis, hives, swelling. These symptoms typically present soon after eating the allergen.

A food sensitivity is noticed more when you see symptoms like bloating, lethargy and headaches. These symptoms may present much later than an allergy and are commonly correlated with impaired digestion. In some cases, we do not have the enzymes to digest these foods (like lactose intolerance) or we have physical impairments (like imbalanced gut bacteria) that impede our body’s ability to utilize certain foods.

How does this affect our weight? There are two common ways.

First, are obvious signs of bloating that feel like weight gain. In some cases, stomach distension is so extreme that one may feel many months pregnant! We can see this in both food sensitivity and gut dysbiosis (imbalanced gut bacteria). On the scale, a person may see no difference, however they notice these changes, physically.

Second is the slow burn. This is when someone gains weight over time via inflammatory conditions. (1) In studies utilizing an elimination diet vs. calorie restriction for those with food intolerances/sensitivities, those in the elimination diet group were able to lose weight compared to the calorie restriction groups. (2)

weight loss food sensitivity hormones gut health


There are a number of ways that our hormones lead to weight changes, including our thyroid, hunger hormones and stress.


It is quite common to see someone with an underactive thyroid dealing with an inability to lose weight, despite dietary and exercise changes, as it is directly linked to our metabolic function.

Those with underactive thyroid naturally burn less energy, even at rest, compared to those with better thyroid function.

In some studies, it is found that triiodothyronine (T3) can regulate our appetite and impact lipid metabolism and treatment with liothyronine provided patients with weight reductions. (3)

As well, thyroid hormone issues can lead to lower energy, resulting in decreased motivation to eat well and be physically active. While this ties back into the calorie rhetoric, the underlying issue is hormone related.

Learn more about your thyroid here.

Leptin and Ghrelin

These two hormones are meant to regulate your satiety and hunger hormones.

When these two hormones’ levels are aligned, our appetite and cravings should be manageable. However, when there are lower levels of leptin or higher levels of ghrelin, we see an increase in our hunger and/or cravings. So what causes this imbalance?

Ghrelin is made in the stomach, particularly when it is empty. Circulating levels in the body increase prior to a meal and decrease after. (4) It is shown that many people who diet chronically may experience an imbalance of ghrelin levels because of this, making sustainable weight loss more challenging.

Sleep can also impact our leptin and ghrelin levels. One study looked at the effects of sleep deprivation over two nights (4 hours of sleep per night). Self-reported hunger was increased, as well as circulating ghrelin, while circulating leptin decreased. (5). Other studies highlight sleep’s role primarily on leptin as it increases through sleep and is linked directly to our circadian cycle, with highest levels in the morning. (6)


Insulin is an important hormone in our body that helps to regulate our glucose (sugar) levels. It uses what we’ve eaten for energy or stores it for later.

However, some people may deal with conditions associated with insulin resistance. Diet is often the catalyst to these conditions, with correlating increased weight. Regulating our blood sugar by dietary support can balance insulin levels. In some cases intervention with supplements or prescription drugs is necessary in the short-term.

Get a full overview of insulin and some conditions associated with its imbalance here.


Cortisol is an essential hormone that helps us to wake up and respond to stressors. However we’re exposed to cortisol releasing situations far more often than our body wants.

For many, high cortisol levels (and subsequent feelings of stress) cause increased hunger and cravings, particularly for sweet foods. (7) How we distribute fat can also be indicated by cortisol levels. Higher stress-induced cortisol is correlated with an increase in the weight around the midsection. (8) (9)

weight loss gut health

Gut health

The bacteria that exist in our gut microbiome help to break down and digest our food. In some studies in mice, dietary changes led to a decrease in cells that protect against weight gain. (10) (11) Additionally, your gut microbes may alter both short chain fatty acids, which impact metabolism and insulin sensitivity, as well as pro-inflammatory cytokines like interleukin-6, c-reactive protein and tumor necrosis factor. (12)

Have you been trying to manage your weight by counting calories? Create an individualized plan with your practitioner.

  1. https://www.scielo.br/j/babt/a/kGWwGx7RfrnpcmyW96GKT9h/?lang=en

  2. https://meditraject.nl/wp-content/uploads/2016/06/Obesitas-door-ontstekingen-geassocieerd-met-voedingsintolleranties.pdf

  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3821486/

  4. https://www.sciencedirect.com/science/article/abs/pii/S0031938406002307

  5. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2869.2008.00662.x

  6. http://pmr.cuni.cz/data/files/praguemedicalreport/pmr_109_2008_04/pmr_04-2008_275.pdf

  7. https://pubmed.ncbi.nlm.nih.gov/11070333/

  8. https://pubmed.ncbi.nlm.nih.gov/16353426/

  9. https://pubmed.ncbi.nlm.nih.gov/11020091/

  10. https://www.nih.gov/news-events/nih-research-matters/how-diet-may-disrupt-gut-microbes-promote-weight-gain

  11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7333005/

  12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7333005/)

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