Another post by our expert registered dietitian, Susan McFarlane. This time, Susan tackles the tricky subjects of hunger, satiety and the factors that contribute to them.
When it comes to successful weight loss, there is no magic pill, powder, or potion that will give you results you want without requiring you to make significant and sustained changes to what you eat and how you move your body. As mentioned in my previous post, to lose weight, we need to burn more calories than we consume. But because there isn’t one way to lose weight, this is where things get interesting. From low carb/high fat, to high carb/low fat, all diets appear to have equal weight loss potential the longer they are followed. So what type of diet should you follow? Simple – the one that doesn’t leave you feeling hungry.
Understanding Hunger and Fullness – The Satiety Cascade (¹)
Hunger is universally interpreted as a cue to eat. For most, it’s experienced as a growling sensation that occurs as your stomach relays information to your brain about how empty it is. At the same time, the “hunger hormone”, ghrelin, increases and fuels our drive to seek out food. This physiological experience of hunger is aided by our learned behaviours about eating (i.e. 12 pm equals lunchtime), the sight and smell of food, and the expectation of reward and pleasure that it brings.
As we eat, our stomach communicates with our brain to tell it how much it has stretched and the number of food particles and water that have been ingested. There is also a release of hormones that not only help us digest food, but cue us to stop eating. Yet, as finely developed as this feedback system is, it can be overridden by the pleasure and reward that food and eating bring. Additionally, beliefs about how filling the food will be, combined with the food’s sensory properties, influence our decision to stop eating (2). Fullness between meals is largely dependent on how quickly the food we eat passes through the stomach and remaining digestive tract.
Finding your Satiety Sweet Spot
Knowing the science behind the satiety cascade is useful since we can manipulate it to enhance the fullness we derive from food. And experiencing greater fullness for a longer duration of time is ultimately the goal since it leads to a lower calorie intake and consequently, weight loss.
Before you Eat
Research shows that our perceptions about the food we eat, combined with sensory properties of the food itself, go a long way in inducing satiety (2). For example, if we are led to believe that the food we eat is going to be very filling, we are primed to feel full. However, this mind trick only seems to work if the sensory properties (i.e. the texture) and the calorie content of the food match our expectations (2). Using a real-world example, if we believe a new smoothie recipe will be filling, and it delivers the sensory properties of thick and creamy while providing enough calories to keep physiological hunger at bay, we are likely to feel fuller compared to a recipe that lacks satiety information and fails to provide a thick taste sensation. Similarly, we can also enhance satiety by tricking our mind into believing we are eating more food than we are by using smaller plates and bowls and increasing the volume of food consumed by adding low calorie fruits and vegetables.
While you Eat
When it comes to macronutrients, protein takes the title of most satiating (2). However, carbohydrates are a close second as fibre (specifically the type of fibre founds in oats, beans, lentils, and flax) is known to enhance feelings of fullness by delaying gastric emptying, positively influencing satiety hormones, and increasing gastric distention (3). Fat, on the other hand, is often rated as less filling (at least in the short-term), despite providing a higher number of calories (4). However, it is not yet clear what the ideal ratio of protein: carbohydrates: fat is in a food or meal when it comes to satiety.
How we eat also seems to play a role in determining the satiety derived from food. Research shows that liquid calories, as opposed to solids, generally leave us feeling less full since the act of chewing enhances both perceived and physiological satiety (5). In addition, distractions such as TV or social media, dilute the sensory information being sent to our brain about the food, which could contribute to overeating.
In the period following meals, it’s important to avoid triggers that lead you to mindlessly eat. TV-watching and reading are two of the most common activities that people associate with eating and can trigger the brain to want a snack, even if hunger isn’t present. Instead, try to do an engaging activity that involves as many senses as possible. Some of my favourites are: knitting with the infuser on while playing music or painting your nails while listening to your favourite podcast.
If you have any other tried and tested strategies for enhancing the satiety you feel from meals, we’d love to hear from you! Leave a comment below or start-up a discussion in one of the forums.
- Amin T, Mercer J. Hunger. Hunger and Satiety Mechanisms and Their Potential Exploitation in the Regulation of Food Intake. Curr Obes Rep. 2016 Mar;5(1):106-12. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/26762623.
- Chambers L, McCkrickerd K, Yeomans M. Optimising foods for satiety. Trends Food Sci Technol. 2015 Feb;41(2):149-160. Available from: https://www.sciencedirect.com/science/article/pii/S0924224414002386.
- Wynne K, Stanley S, McGowan B, Bloom S. Appetite control. J Endocrinol. 2005 Feb;184(2):291-318. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/15684339.
- Blundell J, Macdiarmid J. Fat as a risk factor for overconsumption: satiation, satiety, and patterns of eating. J Am Diet Assoc. 1997 Jul;97(7 Suppl):S63-9. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/9216571.
- Zijlstra N, Mars M, de Wijk RA, Westerterp-Plantenga MS, de Graaf C. The effect of viscosity on ad libitum food intake. Int J Obes (Lond). 2008 Apr;32(4):676-83. Epub 2007 Dec 11. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/18071342