A group of UK researchers have discovered that when they served an omelette to people taking part in their study and told them it was made with four eggs, they went on to eat 167 fewer calories throughout the rest of the day compared with when they were the given the same size and weight omelette on a separate occasion... but were told that it was made with two eggs.
In fact, say scientists writing in the journal Appetite (1), both omelettes had been made with three eggs.
Having found no changes in levels of the 'hunger' hormone ghrelin in the people taking part, the researchers concluded that our perception of what we think we are eating, could play a big role in how satisfied we feel afterwards and crucially, affect what we then go on to eat over the rest of the day.
Reading this research, made me think immediately of 'volumetrics', a term coined by Barbara Rolls (2) professor of nutrition of Pennsylvania State University in America.
While it is understandable to assume that eating smaller portions will help in our quest to solve the bulge, as Rolls and her colleagues have shown over the last decade, this is not necessarily the case.
In fact, it can be quite the reverse. If you pump up the volume of a meal to make it look bigger and yet keep energy levels under control you can end up eating 'more' in terms of volume and weight of food but 'fewer' overall calories.
This is partly because the visual appearance of a meals' size has a huge role in our subjective perception of fullness… regardless of the calories it is actually provides.
Rolls cites one particular study to prove the point. When people were given chicken and rice that was made into a soup, they ate 26 per cent less food at their next main course compared with people served the chicken and rice as a casserole with a separate glass of water on the side.
Both meals had exactly the same total volume of food and fluid entering their stomach and yet the soup, which looked visually 'bigger', ended up being more satiating than the smaller casserole version with the water served separately. This was in part down to the soup version looking bigger but also, explains Rolls, because it seems that when the water is part of a meal it stays in our stomach longer than when taken as a drink on the side. Not surprisingly, when a meal hangs around longer in the stomach, this also helps us to feel fuller for longer, which can impact on future intake of snacks and meals that follow.
Making 'volumetrics' work for you can be fun and its worth playing around with. Check out these further tricks, which can affect what you think you are eating.
Whisking air into a smoothie can make it look like a larger serving once you pour it into your glass, fooling your brain into thinking it's getting more than usual.
You can whisk air into eggs as well, for example, before making scrambled eggs. Doing so can mean that your final dish ends up looking 25 per cent larger than more solid looking versions made with cream and butter.
Try serving dishes with high water content foods. Serving your whisked eggs with two, naturally water-rich grilled tomatoes and five grilled mushrooms gives you a meal that is visually impressive in size, weighs 362g (of which around 315g is water) but gives you just 218 calories and 14g of fat.
An un-whisked version of scrambled eggs made with butter and milk and served with two slices of buttered wholemeal toast on the other hand looks significantly smaller, weighs in at just 230g in total (of which water is only 125g) and yet it packs in 586 calories and 46g of fat.
Not only are you getting loads more calories in the second version, its smaller volume makes it quicker to eat and may well leave you reaching for a further slice of toast to fill you up.
Or how about snacks and dips? A 60g portion of tortilla chips with 75g of sour cream dip weighs 135g and gives you 576 calories. On the other hand, a 60g pitta cut into strips served with 75g reduced fat hummus and 50g each of yellow and red peppers, celery and carrots weighs 365g and has 353 calories. You get 230g more food and 223 fewer calories. It looks bigger and feels more in your stomach and while this can easily be a tasty lunch, the tortilla snacks and cream cheese dip is usually perceived as being 'just a snack'.
If kidding your brain can help you to eat less without feeling deprived, it has to be worth a try. Look out for more examples on my Instagram feed!
(1) We Are What We Think We Eat, S.D Brown et al; Appetite, Volume 152, 1 September 2020, 104717. https://doi.org/10.1016/j.appet.2020.104717
(2) The Ultimate Volumetrics Diet: Smart, Simple, Science-Based Strategies for Losing Weight. By Barbara J. Rolls. Harper Collins. £10.95