Other Factors That Influence Scale Weight

Understanding that the weight you get from a scale is influenced by various factors can help you better comprehend why the scale can be your biggest foe in the “Battle Of The Bulge”.


Scale weight changes constantly throughout the day. Any figure that the scale reports to you is merely a snapshot, a moment in time. The number doesn’t take a whole lot of time to change, and it doesn’t need a reason to shift. Dietician Alexandra Caspero showed you can gain almost two pounds in an hour without any apparent cause at all.

Scale weight is subject to the whims of water. Your intake of H20, or output of sweat, can cause your total body weight to shift up or down by nearly half a percentage point within any given day, according to John Castellani, a researcher at the U.S. Army’s Research Institute of Environmental Medicine.

Your water/salt balance can cause seasonal shifts in your weight, too. When the mercury climbs in the spring and summer, your body uses a hormone called aldosterone to retain more fluid. So what looks like summertime backslide in progress might just be your body’s natural reaction to the warmer weather.

Lastly, if you’re not taking in enough fluids, then your body will hold on to more of them for you. “Mild dehydration may cause fluid retention, which can increase scale weight, “ explains Dr. Melina Jampolis.


Scale weight makes your stress an even bigger deal. Numerous studies show a relationship between elevated stress levels and higher weights. This 5-year long study of more than 5,000 people in Australia found that those who felt the most stress also gained the most weight during that time span.

Stress is also one of the main triggers of binge eating. Combine that with negative reinforcement from the scale and you have a damned unfortunate vicious cycle: Stress makes you eat. Eating increases your weight. Your weight makes you stress.

Making matters even worse, stress increases cortisol production, which has been linked to higher levels of abdominal fat in both women and men.


Scale weight measures gut content. Motility—the polite way of saying “how frequently you poop”—matters when you measure your scale weight. This rate varies from person to person. Your regularity can change based on what, and how often, you eat. (People with an extremely slow rate are said to have gastroparesis, or delayed gastric emptying.) How much you chew your food, whether or not you drink water with meals, and how much you are up and about walking can also influence it.


Scale weight is as subject to change as your flight schedule. Air travel can impact your weight by disrupting not only your circadian rhythm but also the rhythm of the bacteria in your gut microbiome.

A study published in Cell found when mice were subjected to jet-lag-like conditions, the bacteria in their digestive systems changed and the animals gained weight. The researchers found that similar changes took place in the microbiomes of two people who traveled by air from the U.S. to Israel.

In non-scientific terms, you might notice bloating when you travel, which regulates within 24 hours. Are you actually gaining weight while you’re in the air? Of course, not. But the scale might have you believe otherwise.


Scale weight rewards cheaters. You could hack your way down to a target number through crash dieting and stimulants. But you definitely won’t be healthier for having done it.

“You can technically lose weight by cutting your calories by half and eating minimally nutritious, highly processed junk food. But that misses the point,” says Las Vegas-based dietitian Andy Bellatti. “Sure, the number on the scale will be lower, but you probably won’t feel good and you won’t have much energy to engage in physical activity.”


Scale weight does not show the bigger picture. Your weight can fluctuate significantly due to a single meal, making you stress unnecessarily.

Say you’re on a weight loss plan and making progress. So you treat yourself to a heartier meal while you’re out with some friends. That’s a totally normal and healthy thing to do—reward should be part of a weight loss plan. But the next time you step onto the scale, the number you see could try to convince you otherwise.

“The scale plays a huge role in what we call ‘what the hell?’ weeks,” explains Born Fitness Head Coach B.J. Ward.  “People will retain water after an ‘off-plan’ meal, which tips the scale higher. Then they’ll have an emotional reaction.”

People wind up thinking that they aren’t making progress when really they’re just a little bloated. A similar effect can happen among people doing any type of carb cycling, Ward explains. You are going to weigh more after a high-carb day than a low-carb day. In either case, Ward says individual measurements aren’t what matters. The overall trend line is.

“Daily weigh-ins tends to produce mental static,” Bellati says. “Most people don’t know that a high sodium meal the night before can result in retention of 3 or 4 pounds (up to 2kg) of water the next morning, which most people mistake for true weight gain. They then enter an unhelpful and unnecessary spiral of frustration, guilt and self-blame.”


Scale weight is blind to what really matters. The final—and biggest—nail in the “should I sweat over what the scale says?” coffin is this: The scale can’t tell you what you’re really made of.

Plenty of people can step on a scale and hit a low number but be far from healthy. There’s even a term for it: “skinny fat.” On the flip side, the scale—and its derivative BMI—is prejudiced against people who carry more muscle. Which is why BMI will tell you that every player on the Denver Broncos is overweight or obese, even though our own eyes can tell us that Von Miller is friggin’ jacked.

Muscle and bone are denser than fat. Stronger people may weigh the exact same—or more than—fatter, weaker people. The stronger people aren’t worse off because they’re heavier. In fact, strength is connected to longevity. The raw number on the doesn’t tell you the body fat percentage of the person standing on top of it.

Two people might both weigh 180 pounds. One is 10% body fat. The other is 20%. The first will be lean and muscular. The second will be soft and more prone to a variety of health problems (because of the higher body fat percentage). But the scale doesn’t know or tell you the difference.

All of these reasons are why no good dietician or coach would ever suggest that you focus on scale weight alone. “I think of health as a 20-piece puzzle,” Bellatti says. “Scale weight is just one piece.”

Jessica Robertson, RD at Indianapolis Fitness and Sports Training, agrees. “Weight is one tool, but never something that I focus on or set specific goals around.”

Winning the Battle of the Scale

When you want to make a positive transformation with your body, start by letting go of the temptation to allow a single number to determine your success or failure. Then get a clear picture of your starting point.

The four-part assessment above will tell you a lot about your body. But you’ll also want to examine your habits: how well you are eating, sleeping and hydrating, and how much activity you get in a typical week.

For example, one of our new coaching clients will keep a food journal for a few days when they are first starting out. The journal itself is simple—you just write down everything you eat in a day—but admittedly time-intensive. Which is why we don’t require or even recommend that people continue to do it over the long-term (although some find that they like journaling, and do keep doing it).

The goal with these few days of journaling is just to learn what you are really taking in during a typical day. Sometimes you’ll be able to spot hidden sources of calories in unexpected places.

“I recall a situation where it turned out that a client was adding about 600 calories to a salad via a ‘healthy’ vinaigrette dressing,” Bellatti says. “Once we addressed that, the number on the scale started to move.”

You’ll want to learn about your sleep habits, too, because numerous studies have shown that people who get fewer than 7 hours of sleep per night are more likely to be obese.

When we cut our sleep duration short, our bodies produce more ghrelin—a.k.a. the “hunger hormone.” This happens after just one night of sleep deprivation. Making matters worse, when we’re tired, we’re more likely to crave high-calorie foods. So the more we can do to improve our sleep duration and quality, the better we’ll be able to reach our weight loss goals.

Just like it has with sleep, science shows that your hydration level strongly influences your overall body weight—and not just water weight. An examination of nearly 10,000 Americans spanning three years found a clear association between inadequate hydration and obesity. So yes, the old “8 glasses a day” rule isn’t a bad goal. But if you’re the type who doesn’t love the non-taste of H20, take heart: you can also increase your hydration levels by eating more fresh fruits and vegetables.

We’ve talked a lot about your body and what influences it. But there’s one other critical aspect of sustainable weight loss we haven’t discussed: Your mind. Mindset is a key determinant of weight loss success. Bellatti says that one way to get your mind right is to start appreciating your body, no matter what state it’s in currently.

“When you appreciate something, you want to take care of it,” Bellatti says. “Something as simple as changing the thought process from ‘I hate my body’ to ‘I want my body to operate at its best’ provides an important shift.”

About the author: Brian Kitching
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