Last Updated on 7 March 2024 by Brisbane Livewell Clinic
At the peak of Winter, it’s common to eat a little more, but an insatiable appetite can’t always be blamed on the weather. Appetite control results from metabolic, behavioural, and environmental factors (1) and willpower alone won’t always override the orchestra of influences on our diet choices. With peptide hormones like leptin and ghrelin, the gut-brain axis and stress hormones all influencing our palate and portions of food, let’s see what tantalises our tastebuds and ways to combat an unruly appetite.
The Key Players – Leptin and Ghrelin
Leptin, ghrelin and other gut-derived peptides represent the main appetite controllers. (1) These main drivers are all produced by organs outside of the brain, leptin by adipose tissue, and ghrelin in the gut. (2) Leptin is a peptide considered to be a ‘satiety hormone’ that plays an important role in long-term energy balance, whereas ghrelin is a hormone that controls short-term appetite regulation and is considered a ‘hunger hormone’. (3)
Leptin: (4)(5)
- signals satiety
- is produced in proportion to body fat mass
- is a marker of energy stores
- sends signals for food intake by increasing appetite
- increases after several days of overeating in humans
- levels fall dramatically with fasting and starvation
Ghrelin:(5)
- is secreted by the gastric mucosa on an empty stomach
- stimulates appetite
- is suppressed by ingestion of food
- increases thermogenesis (fat burning)
- increases insulin secretion and its sensitivity
Gut Feelings
The gastrointestinal tract is a highly specialised sensory organ that provides negative feedback during a meal, partly via the gut-brain axis. (6) Regulation of appetite is dependent on the crosstalk between the gut and the brain, which controls appetite and satiety via various signals, regulating energy balance, controlling food intake and energy expenditure. (7)(8) Gut microbiota has been shown to provide a substantial metabolic contribution to the host, (6) indicating that probiotics may have an important role in appetite regulation.
Stress and Sugar
Chronic stress promotes insulin resistance and preference for energy-dense foods (4) which overwhelms the regulatory system, easily overriding the pathways of appetite regulation. Stress aside, food has pleasurable and rewarding qualities which drive appetite beyond metabolic needs. (8) The food and drug reward pathway seem to converge within the limbic system of the brain. Increased stimulation by highly palatable foods (high sugar/high-fat content) seems similar to drug reward and addiction, (4) also overriding the normal regulatory systems when it comes to appetite and satiety.
Deprivation and Excess
An important thing to note is that undereating can trigger overeating. Food restriction and fat depletion lead to a ‘hungry’ brain, preoccupied with food. (9) Low levels of leptin indicating food deprivation and depleted fat stores have been identified as the strongest signals to induce adaptive biological actions such as increased energy intake and reduced energy expenditure. (9)
Spice it up
Generally, we tend to overeat sweet and salty foods and consume less bitter or sour foods. (8) Incorporating chilli into meals may be a simple way to curb appetite. In two studies conducted to investigate the effects of red pepper (capsaicin) on feeding behaviour and energy intake, the first study indicated that the ingestion of red pepper at breakfast decreases appetite and subsequent protein and fat intakes in Japanese females. The second study showed an overall decrease in energy intake in Caucasian males when chilli was incorporated into their lunch meal. (10)
Adjusting your Appetite
Adjusting your dietary strategy can be an individual process, with eating enough being equally as important as preventing overeating. A new dietary approach can often be adequate to improve appetite regulation and there is always support available with our team of natural healthcare providers, who can help to implement diet change that complements your needs.
We’ve written several blogs to keep you well informed on the broader aspects of this topic including Identifying Insulin Resistance and The Seriousness of Sugar. Of course, these are conversations we have daily at the clinic, where Food as Medicine is our way of helping you to Livewell.
