Why do liquids feel like ‘less’ food?



Since I started drinking more soups and smoothies and less solid foods, I have dropped a bit of weight. Not a lot, just a few pounds. In addition, I feel less ‘full’ after having liquid meals.

Why is this? Shouldn’t calories be the same, regardless of whether something is in solid or liquid form?

For example, I had a smoothie with two bananas, a cup of blueberries, and two cups of oat milk today. I could never bring myself to actually eat two bananas, a cup of blueberries, and two cups of oat milk *separately,* but blended together I can consume all of that, no problem. Why?

In: Biology

Your body has to digest the solid foods more than the smoothie. The process of blending the smoothie does most of the work of chewing, the first phase of digestion.

If you crumble pieces of paper and throw them in the waste bin, you’ll find the bin can only hold some 10s of sheets. Now, use a shredder on the paper before emptying into the bin and you’ll find the bin can hold 100s of shredded sheets.

The blender is the shredder for your food, cutting it up to smaller bits than your mouth can. Thus, blended smoothies fills less volume in your stomach than chewed food.

As for your weight loss, your example with the fruit smoothie should be the same calories if you ate the food or drank it blended. You’ll have to consider other parts of your diet. You said you’re drinking more soups. Our body can mistake dehydration for hunger, making us eat or snack more than intended. Soup would help relieve your thirst as well as hunger.

Solid food is also more calorie dense and harder to judge portions unless you have a scale. Meanwhile, you can easily measure out portions of soup and smoothie in a cup or bowl. You may be doing a better job tracking what you’re eating.

Think of your stomach like a bucket with a holes in it.

Liquids pass through with relative ease, where as solids need to be decreased in size through digestion until they’re small enough to pass through the hole.

Your stomach sends a message to your brain when it’s full, and as liquids are passing through quicker than solids, it can stop the message being sent.

Another interesting point on calories is how many you consume drinking juice Vs whole fruit. For example, a glass of orange juice is like 6 oranges… But try eating 6 oranges at once.

In the span of human evolution, there has only been a very short time when people ate very calorie dense food. It’s very labor intensive to refine sugar or even just gather many berries and nuts and put them in one food if you are doing it by hand. Our body has hormones for satiety and hunger, but it’s mostly adapted to “make sure you get enough of that sweet (high calorie) thing”, completely unprepared for the floodgates to open so wide and get so many calories from small sources.

Satiety is dependent on a lot of factors, one of the *least* of which is total caloric content.

The primary differences are chewing and presentation. Chewing begins the digestive process, and releases hormones that make you less hungry. As far as your body is concerned, you’re chewing food, we don’t have to worry about your hunger anymore, its time to think about how we’re gonna track down that puma tomorrow. You skip this step when you drink a protein shake. As far as your body is concerned, if you’re drinking, its water and it should make you feel less thirsty but we still have to worry about hunger.

Presentation also matters. When was the last time you drank a protein shake from 2 glasses?

In a study where participants were fed soup and asked to rate their hunger levels before and after, participants in one condition had to refill their bowl from a pot and participants in the other condition were given a bowl that refilled itself as they ate from it. Participants who ate from the never-ending bowl of soup not only ate more soup on average, they also rated a smaller change in their hunger levels. When you drink a protein shake, its probably from a single cup. Which makes you feel less satiated because “well I only had one, how filling could it have been..?”

I got hooked on smoothies when I had my jar wired shut for 6 weeks. I learned to add a raw carrot and cottage cheese or yogurt to my smoothies. I think the protein helps to make me feel more full.

My typical breakfast is a smoothie made from a a grapefruit, orange, big carrot, a pear or apple, a frozen banana, and a handful of frozen random fruits, with about a generous half cup+ of cottage cheese and enough juice to make it drinkable with a straw. I’ll feel full until dinner with that.