My wife is a PE teacher and this month she is teaching the kids about healthy eating choices. She is a virtual teacher and works from home, so I get to listen to her lessons. It got me thinking about gaining weight and the foods we eat. Can you put on more weight from eating something than the item itself weighs?
I realize that for the most part only a fraction of what we eat ends up as blubber on our waistlines, but how much physical weight of food is actually retained or is the weight of the food irrelevant?
Under certain circumstances it may be theoretically possible to gain more weight than the weight of the food consumed.
If you were to deplete your liver and muscle glycogen stores via fasting or exercise, weigh yourself, then consume some carbohydrate, you could potentially gain more weight than the weight of the carbohydrates consumed since every gram of glycogen stores 3-4 grams of water along with it.
Yes, if you retain water, but that generally isn’t permanent weight. On the other hand, you CAN gain more weight than would be suggested by caloric ratios; in other words, a pound of fat is 3,500 calories, but a pound of muscle is considerably less because muscle is mostly water (not sure about human muscle*, but muscle is around 75% water; thus, one pound of dry mass makes four pounds of muscle; fat is just stored in existing tissue so 3,500 calories of fat pretty much gives you a pound).
*If one uses the numbers here and beef is similar in composition to human muscle, there are only around 500-600 calories in a pound of muscle, but muscle also needs additional energy to make it.
Yeah I was very confused about this too when she took the position. However, seeing it in practice it all makes sense. The course is mostly about learning to eat healthy, learning about things like proper heart rates and exercising properly. A lot of book work. Any physical requirements have to be done in front of a parent and the parent has to verify the student did it. This week most of the students are working cardiovascular heath and learning what to do to keep the heart healthy. I still find it strange, but it works. The course is called Personal Fitness instead of PE.
A pound of lard has over 4000 calories, while a pound of body fat has roughly 3500 calories. This means if you eat a pound of lard over and above your caloric needs for the day, you will gain more than a pound of fat.
Of course, this ignores water weight and other non-fat components of body fat tissue, which had to come from somewhere. Mass is of course always conserved. So in general the answer is “No”.
I have no knowledge of what is going on when you metabolize food, but to all those who say no I have to ask if you are sure? I know that when you burn gasoline, you create 19 lbs of co2 for every lb of gasoline burnt due to the addition of oxygen molecules, can’t something similar happen when you metabolize food? This would be a gross gain, not net, but I also think that DrCube’s comparison of calories per lb for lard is informative.
In fact, it’s my understanding that we excrete more through our lungs than any other system over the course of a day. We turn our fat into CO2 and then trees turn it back into wood.
I’m a bit confused here. The OP asks about weight added and weight retained.
But our bodies are not just empty sacks into which we put certain weights of food. The body is also an engine that produces energy from that food, and stores some it.(usually around my waistline )
If I eat a pound of carrots, I’ve put a single pound of weight in my stomach.
I’ve gained one pound of weight. Temporarily.
If I eat a pound of ice cream with fudge, I’ve also put a single pound of weight in my body.
But I’ll gain more than one pound. Not temporarily… (don’t ask me how I know this )
Now we all know which of those one-pound meals is going to make you fat. And the OP asks why.
Isn’t it because the relevant issue isn’t the weight of the food— it’s the energy (calories) within the food, which my body burns partially to keep me alive, and stores the rest.
The OP is teaching children about healthy eating, not about Newtonian physics.
So you may not gain more weight than the actual weight you consume.
But, over time, you will retain more weight from certain foods than others.
The weight/amount of the food is just part of the equation, what also factors is the food’s caloric density. For example, 1 lb (454g) of iceburg lettuce is 64 calories yet 1 Snickers bar (57 g) has 270 calories. Fat accumulates when caloric intake exceeds metabolic needs which would be difficult with iceburg lettuce but quiet easy with snickers bars.
Only slightly related to the OP, but when else would I get to tell this anecdote:
20 odd years ago when I got my first puppy, I was astounded at how fast he was growing. So much so that I decided to collect some data:
While consuming the second 20# bag of puppy chow, he gained 12.5#, for a chow to puppy conversion efficiency factor of over 50%. I did not take measurements, but it is my belief that he also produced over 10 lbs. of poop in this time.
Back to the OP: If it could be done (weight gain > food eaten) it would be done by a puppy.
I calculated a number for it in another recent thread on this topic. About 125-250 lbs of the food you eat in a year is exhaled as the carbon component of CO2 (the total weight of the CO2 is much higher, but the O2 part came from breathing, not eating). This is ignoring water entirely.
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