Finding The Sweet Spot: Balancing Calorie Density, Nutrient Density & SatietyJeff Novick, MS, RDN
Q: If I haven't eaten and am feeling hunger pangs, stomach growling with an empty feeling, and I drink a glass of water, does that quiet the feeling of being hungry, even if temporarily? Yes, it is possible but will be very temporary.
Q: Not talking about meeting nutritional requirements, just acute hunger signals. Ive momentarily filled my stomach, so don't feel hunger pangs. Again, yes possible.
Remember, satiety is defined in medical textbooks as the opposite of hunger and satiety has certain aspects to it. Bulk, from the water and the fiber in foods, is important, as is the weight of the food as are the calories.
So, water can provide a temporary feeling of satiety but it will not last long term or meet our nutritional needs.
Q: In a discussion, someone stated that they ate soup and it was so filling they couldn't finish what they served themselves, however also stated that they felt starving still. Can one fill a stomach to capacity and still feel starving? Yes, in a way.
Q; I likened to filling my gas tank to capacity and expecting to not see the gas gauge read empty. I know the stomach stretches and we have stretch receptors but also need a certain weight to feel full, but I would think that not being able to finish a serving cause you're too full wouldn't leave you feeling starved, at least not physically. Sometimes, people are trying to describe something they are experiencing and using words and terms they know but it may not be adequate or accurate. This is why part of the role in helping someone is first to understand what is really going on. This in and of itself, can be difficult. Her comments in regard to "starving" may be referring to something different that you and I mean.
However, having said that, yes, it is possible and here is why. It is what I am calling the "J-Curve Paradox" of calorie density/nutrient density/satiety.
Generally speaking, as calorie density goes down, satiety goes up (as does nutrient density). So, if I was to plot the two against each other, in a 2D graph, it seems fairly simple, to have the lowest calorie dense, highest satiety, nutrient dense diet, eat very low on the scale.
However, there is another factor that is important, that you mention, and that is weight and to really understand this issue, we have to plot 3 axis and make it a 3D graph.
Here is why, studies have shown that humans consume a certain weight of food per day, regardless of the calorie density and/or nutrient density of the food. And, the size of the vessel we are filling (the stomach) has a fairly standard and limited size (with a range of variation). On average, it is about 4 lbs of food a day with a 3-5 lb average.
If we need about 1800-2500 calories per day, we need a calorie density of 450 to 625 with a range of 360 to 833.
This is almost 100% identical to what i have been saying in regard to calorie density, and is what is recommended by the WCRF/AICR report.... 400-800 calories per pound (rounded off)
So, if you go to low in calorie density and your CD is under 300 cal/lb, at even 5 lbs of food, you would barely make 1500 calories and for most people doing the minimum activity, that is too low. At 3 lbs of food you are at 900 calories and starving.
An all fruit and veggies diet, would average under 300 and actually be closer to 150-200. At 3-5 lbs that is only 750 to 1000 calories.
So, by going to low in calorie density (ie, vegetables, vegetable soups), we can fill up the volume of our stomach but without enough weight or calories. In addition, because these foods are so high in water content, around 90% or more, the water does leave somewhat quicker than the food, so the satiety is not as long lasting.
In the actual satiety studies, they saw this with the high water foods, like fruits and veggies. They were very highly rated in s/t satiety but not in l/t satiety. Turns out the starches, like potatoes, oatmeal and whole grain pasta where the most satiating both short term and long term.
Now, when we add in the weight aspect to the calorie density/nutrient density/satiety issue, along with stomach size, it all make sense.
For instance, lets say the average stomach size is 1 liter or about 4 cups. Not only do we have to fill it with a certain amount of food volume/bulk to trigger satiety, the weight of this "bulk/volume" of food will also matter.
Let see....
4 cups of lettuce has only 32 calories and is very high in nutrient density but only weights about 188 grams and 95% water.
4 cups of apple sliced has 226 calories, fairly high in nutrient density and weighs 436 grams and 85% water.
4 cups of cooked sweet potato has 720 calories, high in nutrient density and weighs 800 grams is 75% water.
So, based on everything we know, which would be more satiating both short term and long term?
Remember the foods which will provide a combination of the most weight and the least calories for the same volume will be the most satiating per calories, but the foods with the higher percentage of water will leave the stomach sooner.
Sweet potato, then the apples, then the lettuce.
So, one can actually go to low in calorie density and fill the stomach with enough bulk volume but from foods that have to high a percent of water and not enough weight for the volume that they will not have as much long term satiety.
This is why the issue is not just calorie density or just nutrient density of just satiety but a combination of which food(s) provides the best of all three.
This is also why the pictures showing how much an equal calorie amount of different foods fills a stomach is not enough as it only looks at the issue of volume & not weight/volume, etc. The above scenario of lettuce, apples & sweet potatoes are all the same volume (4 cups) but there is quite a difference in their overall satiety.
We often see this issue arise in those who are shunning or limiting the food groups of whole grains, starchy veggies and legumes. They focus to much on the fruits and/or the veggies and while they can get in enough bulk and volume, they are not getting in enough weight (and calories) for that volume to feel really satiated long term. So, they end up either going hungry during the day, which is hard to do, or the end up over consuming on the higher fat, higher calorie dense foods (ie, nuts/seeds, dried fruit and the foods and "treats" made from them) or binging on higher calorie dense junk foods.
On the flip side, we can fill the stomach with foods with a much lower water content but the calories will then be to high and the nutrient density and the volume per weight to low for good health and satiety. This is akin to the Standard American Diet. So, we end up passively over consuming calories.
This is why in the principles of calorie density, I teach mixing the calorie density of foods from the starches, legumes, and whole grains, with the lower calorie dense fruits and veggies, up to 50/50 by visual volume. This is the sweet spot where you get the benefits of calorie density, nutrient density & satiety all together.
So, if one uses the above scenario and mixed a plate with 2 cups of sweet potato and 2 cups of vegetables (the 50/50 guideline), we now get the same bulk/volume (4 cups), enough weight/volume for long term satiety, and a high nutrient density for good health We have almost 500 grams and only 375 calories.
It may not be the lowest in calorie density, or the highest in nutrient density, but it is the highest in satiety both s/t and l/t and the best combo of all the issues. This way, one gets enough both bulk/volume and enough weight to confer both s/t and l/t satiety, with a low enough calorie density to either lose or maintain weight, with a more than adequate nutrient density to insure optimal health. Its a win/win/win.
I hope that helps
In Health
Jeff