One of the most challenging aspects of dieting for losing weight is hunger. As a quick review, body fat is energy storage – if you consistently eat more energy (measured in calories) than your body uses, you will store it as body fat. If you consistently eat less energy (calories) than your body uses, it will tap into your stored energy (body fat) reservoirs. Dieting for fat loss literally means eating giving your body less energy than it needs for maintenance, so it pulls from your stores of body fat. This process sounds great, but it comes with a few side-effects – namely, hunger.
What’s the best way to fight hunger, without going overboard on calories (thus preventing fat loss)?
The simple answer with slightly more complex applications is to eat more filling foods.
Is there a way of quantifying how filling a food item is? Well yes, I’m glad you asked…
What makes a food filling in the first place?
To keep things simple, there are 3 main ways that foods can serve to fill you up:
1. Volume. This one is pretty self-explanatory: when you physically fill up your stomach, the stretching of your stomach lining sends fullness signals to your brain.
2. Calories. Even when volume is equated, foods or meals with different calorie counts will have different effects on your fullness initially. Higher calorie foods or meals send signals to your brain that you have eaten more/enough calories to reach ideal energy levels.
3. Macronutrient Make-Up. The protein, carbs, and fats make-up of your food or meal will impact how full you feel while that food is digesting. For example, the process of breaking protein down and absorbing protein has been shown to lead to greater levels of fullness, initially and for prolonged periods.
If you are restricting calories in order to lose body fat, the second mechanism regarding calories will be the least helpful of the three, and you will do best to rely more heavily on the first and third: volume and macronutrient make-up.
Using these revised guidelines, we can create a list of food/eating patterns to help keep fullness higher while keeping calories lower:
1. Focus on Volume
– foods with high water content, such as vegetables, fruits
– foods with high fiber content, which takes up space without many calories, such as vegetables, fruits, whole grains
– foods with high air content from chewing, such as popcorn
– limiting food items that have extremely high calorie density for their volume, such as nut butters, sauces, cooking oils
3. Focus on Macronutrient Make-Up
– foods with high protein content, such as animal products, Greek yogurt
– mindful portions of foods with high fat content, such as dairy products, cooking oils
– limiting food items that have high sugar content, which boost calories without boosting fullness, such as candy, pastries, sodas/juices
The Satiety Index
In terms of quantifying how filling a food item is, researchers from the University of Sydney conducted a study in 1995 named “The Satiety Index of Common Foods.” The outcome is a list 38 food items on a graph which shows how filling (or satiating) they are. In the study, participants were monitored every 15 minutes for two hours after eating 240 calories-worth of each food item. With a series of different metrics (which were compared to white bread as a control), foods were given a satiety score. A higher score equates to a greater satiety level. Take a look at the graph below which was pulled from the study.
The very first thing that you’ll probably notice on this graph is a major outlier across all foods groups: potatoes.
If you talk to anybody who has ever looked at this study or used this graph for health/fitness purposes, they will inevitably tell you about how insanely high potatoes scored against other items. Check out that potato bar – it’s the only food to cross the 300 mark, much less almost reaching 400! These numbers are percentages, meaning 300% and 400% as satiating as white bread.
The next thing you’ll notice is that the two categories that did “best” overall were the protein-rich foods and fruits. This is no surprise, given the 3 mechanisms of fullness that we discussed earlier. Likewise, the flip side that is equally unsurprising is how “poorly” the bakery products and snacks and confectionery categories performed. These two categories are filled with foods that are higher in sugar and higher in fat, rendering both categories largely not satiating for the study participants.
It’s important to note that from a health and fitness perspective, the findings of this study don’t delineate “good foods” versus “bad foods.” This is the topic for another post on another day, but I strive to help me clients (and you!) to move away from outright praising or demonizing foods and food categories. Rather, this study points the reader (you!) to view foods in relation to your goals. If you are working on eating in a calorie deficit for losing body fat, you might think or foods as being “more filling” versus “less filling,” or even “more helpful” versus “less helpful.”
In light of all this, what’s the takeaway for you? What can you apply to your our life, right here right now?
Let’s go back to the list of patterns that we created earlier. Use this list to help guide your food decisions, and add to it along the way as you find what works best for you personally. Remember, studies can show overarching trends and enlighten the truth behind the science, but you know your life and lifestyle best. Apply this knowledge in a way that’s meaningful to you and your goals!
Food/eating patterns to help keep fullness higher while keeping calories lower:
1. Focus on Volume
– foods with high water content, such as vegetables, fruits
– foods with high fiber content, which takes up space without many calories, such as vegetables, fruits, whole grains
– foods with high air content from chewing, such as popcorn
– limiting food items that have extremely high calorie density for their volume, such as nut butters, sauces, cooking oils
3. Focus on Macronutrient Make-Up
– foods with high protein content, such as animal products, Greek yogurt
– mindful portions of foods with high fat content, such as dairy products, cooking oils
– limiting food items that have high sugar content, which boost calories without boosting fullness, such as candy, pastries, sodas/juices