Let’s make this clear. I am, what some might (and frequently do) call, hollow legged. I am not one of those people that thrives off the hunger feeling during a fat loss diet, knowing that I’m well on my way to seeing that 6 pack staring back at me in my selfie. I enjoy being so full that I can’t imagine eating for days (and yet managing to eat in another few hours). To put it bluntly, I’m a bit of a pig. As you can imagine, the concept of dieting somewhat antagonises these life enjoyments, so I’ll do anything I can to make the process that much easier. Now the mental side of dieting I can deal with, I’m a pretty positive person so I can remain that way throughout (minus a few squat rack tears). But the physiological signals my body gives off aren’t so hard to ignore (turns out sweating through my clothes on a walk home because I’m so hungry and dazed isn’t a look I can quite pull off). So as I take myself through my first diet phase and as an experiment, I’m going to try some things to try and reduce my diet-induced hunger, and I’m going to start with manipulating the energy density of my diet.
What is energy density?
Energy density, simply put, can be described as the amount of energy (in kJ or kcal) in a gram (g) of given food. For example, for carbohydrates and protein, the energy densities are 4 g/kcal (i.e. for every gram of carbohydrate or protein you eat you get approximately 4 calories), whilst the energy density of fats is 9 g/kcal. In terms of foods, the energy density of broccoli is 0.34 kcal/g, whereas the density of butternut squash is 0.45 kcal/g. So, calorie for calorie, I could eat 130g of broccoli to get the same number of calories as just 100g of squash. Ok, so I know you could lick 30g of broccoli and it would be gone. But when you consider that’s 30% more food you can consume just by choosing the mini trees over the squash, and if you repeated this for every meal (I certainly don’t eat broccoli for every meal quite yet), that’s quite a lot of extra food (extra food is always a term I take seriously).
What the research suggests
Barbara Rolls has provided a great deal of research in to the concept that she has termed “volumetrics”, and has produced a number of journal articles and books detailing the ins and outs of manipulating energy density and the benefits of doing so. Her work is definitely something to read if you want to know more and learn some of the tricks of the trade. I’m just going to touch on a few points here.

In a study where women were given free access to meals of different energy densities (low, medium, or high) on three different occasions, they consumed a similar amount of food (by weight), regardless of energy density. The women, therefore consumed significantly more calories during the high energy density trial compared to the medium and low energy density trials. Importantly, there was no difference in hunger or fullness between these groups, suggesting that energy density affects energy intake independent of macronutrient content (Bell et al., 1998). If you can eat the same amount of food and have the same hunger after your meal, but consume less calories, that’s definitely good news when dieting! Generally, diets low in energy density have been suggested to improve weight loss and weight maintenance

Lowering the energy density of our diets
There are two key ways that we can reduce the energy density of our diets. Based on the energy densities of each macronutrient, one obvious way to do this is to reduce the amount of energy dense fat in the diet. However, most of us prepping for a show or competition have specific macros to meet and manipulating isn’t ideal (and also, fat tastes amazing – hello nut butters of dreams). A simpler way to reduce the energy density of food is by adding water (the energy density of water is 0). Seems obvious, but simply adding water to food automatically reduces the energy density i.e. there is a greater volume for the same amount of calories. In other words, you get more bang for your buck, and that can never be a bad thing.

One of the greatest films ever made… and highly relevant of course
How can you manipulate calorie density to your advantage?
Try choosing foods initially with a lower energy density (all food packaging contains kcal/100g, so just use these as reference values). Try mixing up your macro sources. For example, sweet potato contains 0.9 kcal/g, but cooked white rice contains 1.3 kcal/g. So, if you’re aiming for 100kcal of carbs, you could have about 110g of sweet potato or about 75g of (cooked) rice, I know what I’d rather have!

If you’re on a super strict meal plan, the easiest thing to do is find recipes that involve adding volume to the food you have to eat. For example, I struggle on the few days I have a meal with no carbs (just writing that makes me sad). So I’ve found that, instead of having 100g (or approximately 3 stalks) of broccoli, blending the cooked stuff with lots of stock and flavours makes a pretty decent soup, and at a litre per serving, is far more filling that the cooked broccoli that I could inhale within 30 seconds. Not only that, consuming a low-energy-dense soup before a meal can significantly reduce subsequent meal intake without affecting hunger or feelings of fullness (Flood and Rolls, 2007)

Finally, a study comparing the two main methods of reducing calorie density (added water, or lower fat), alongside a comparison with increased fruit and vegetable intake, found that overall daily energy intake was lower when fat was decreased in meal starters compared to adding water or increasing fruit and vegetables. Ultimately however, all three methods of reducing calorie density were effective in reducing calorie intake across the day without resulting in differences in hunger between methods (Williams et al., 2013). So whatever your preferred method, lowering the energy density of your meals in some way might help curb your appetite if you’re on a set meal plan, or even reduce the amount you eat if you’re just looking to regulate your energy balance.

Today’s lunch – 3 baby stalks of broccoli or a litre of warm soup as a starter?

So why not try playing around the energy density of your diet and see how much more volume you can eat, without the added calories? Oh also, this works both ways. If you’re ‘bulking’ and struggling to eat enough calories (you strange, strange people), look for foods with higher energy densities instead. Happy eating! 

Bell, E. A., Castellanos, V. H., Pelkman, C. L., Thorwart, M. L., & Rolls, B. J. (1998). Energy density of foods affects energy intake in normal-weight women. The American journal of clinical nutrition, 67(3), 412-420.

Flood, J. E., & Rolls, B. J. (2007). Soup preloads in a variety of forms reduce meal energy intake. Appetite49(3), 626-634.

Williams, R. A., Roe, L. S., & Rolls, B. J. (2014). Assessment of satiety depends on the energy density and portion size of the test meal. Obesity, 22(2), 318-324.


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