I received a question on Twitter today that I thought warranted a blog post. @dasschus asked “how long does it take for a surplus of calories to show up as a weight gain? How long until is shows as stored fat? Curious.”
The answer to this question is pretty complex & like everything in health & the human body, what may be the answer for one person may not be the solution for all. Therefore, I’m going to answer this question from my own personal experience.
The short answer is that it doesn’t happen instantly. That’s good and bad news because just as one day of eating poorly isn’t going to derail your weight loss goals, neither will one day of excessive activity make a noticeable difference either. The body ultimately takes an average of my calories in & calories out over a period of time. I notice a lag time of about a week.
That being said, we all notice weight fluctuations on the scale that can happen instantly. Those weight fluctuations are typically water & waste; not fat. Scale weight is very deceiving because it doesn’t accurately reflect our intention for losing weight. In actuality we want to lose fat & the scale doesn’t accurately reflect that. Our scale weight is determined by fat and lean mass. Lean mass is typically defined as muscles, but also organs, bones, water and waste (stuff in our stomachs & bowels). One pint (two cups) of water weighs 1 lb. There are a number of factors that determine how much water the body is holding: hormones, carbohydrate levels, lean mass, and sodium levels.
- hormones – most women experience bloating and weight fluctuations at different times of their cycles by no fault of their own. At this time in the menstrual cycle, the hormone levels in a woman’s body are high, which causes gas and stool to move more slowly through the intestinal tract.
- carbohydrates – when we eat carbohydrates, the carbohydrates are broken down & stored in our muscles and liver in the form of glycol. Each molecule of glycol stores four water molecules along with it.
- lean mass – muscle is comprised of ~75% water, where fat will hold ~25%. Additionally, the more lean mass you have, the more glycol your body can store.
- sodium levels – when your electrolytes are out of balance (typically through consuming too much sodium), your body will retain water until they are back in balance.
Okay – so now you can see why folks who are on low carbohydrate diets will see quick fluctuations in their weight: because as they deplete the glycol in their muscles by not eating carbohydrates, their muscles are also shedding water. Then, if s/he eats a large amount of carbohydrates s/he will see a weight gain because where their muscles were depleted of glycol before, they are now replenished & the water is added too. Therefore, the more muscle you have, the more glycol and water you can store.
I personally don’t intentionally keep my sodium levels low. I tend to not eat processed foods, which is where high sodium lurks. But, I can tell immediately when I eat something that is high in sodium because my fingers swell. The best way to reduce swelling is to drink lots of water. It reduces the concentration of sodium in your system & will help you shed that water that the body is holding on to.
So, let’s say it’s a holiday & you’ve eaten foods that you haven’t been eating in a while. The next day, when you weigh yourself, you’ll notice a huge gain in weight. Typically those foods that we eat in social gatherings are high in sodium, carbohydrates and low in fiber. Since fiber helps food move through our digestive tract, we have the physical weight of the food in our bodies, and the retained water from over-indulging on carbohydrates, and sodium.
Even if you overate for your calorie level for that day, if you’re in a calorie deficit or equality for the week, the over eating should not show up on the scale long term (as fat). You will notice that the scale will go up immediately, but fear not. Resume your normal eating and exercise routine & all of that water weight will fall off again. I notice that the fruits of my labor usually take about a week to show up as fat loss or fat gain.
And for what it’s worth, I don’t weigh myself for at least a week, if not two, after I’ve come home from vacation.