Why the Scale Lies: Water Retention Masterclass

by | Dec 22, 2022 | Featured | 0 comments


Anyone who has dieted before or attempted to diet knows the plight of water retention and how confusing and frustrating it can be. Let’s say you’ve been dieting religiously; weighing and measuring every ounce of food that goes into your body to ensure you’re in a deficit. 

Yet when you step on the scale you’re up 4lb from 3 days ago and your stomach looks even jigglier than it did a week ago. What’s going on here? The answer is likely excess water retention. Many different factors contribute to water retention from hormonal responses, electrolyte imbalances, and much more. 

The Negatives of Excess Water Retention – Emotionally and Physiologically

To the un-informed, water retention can easily cause second guessing of your current plan and negative emotions that can potentially cause the “screw it” effect and subsequently go off plan. 

Even to those that are informed about its normal fluctuations and causes, water retention during dieting can still very much mess with your head. This is one of the values of having a coach, even if you’re a coach yourself. If you’re prone to negative emotion and rumination, an objective set of eyes can go a long way in keeping you on track. 

Water retention is also the main reason that a smart coach would advise weighing on the scale every morning in the same conditions, but emotionally divorcing yourself from that number. 

Since water weight fluctuates daily, we need to really pay attention to 7 day averages of weight, and compare the last 7 day average to the current 7 day average; this will tell you if we’re really making progress. 

Besides being a vanity thing, increased water retention can contribute to high blood pressure as well, depending on the context. 

If someone is lean and otherwise healthy, the effect probably won’t be noticeable. However, in the context of someone being quite overweight or having a history of blood pressure issues, water retention has a real potential to further increase blood pressure.

One of the factors contributing to blood pressure is just how much fluid volume you have within your arteries. Basically, if there’s more fluid, there’s simply more volume pushing out against those arteries, potentially increasing blood pressure.  

We only see the increased water retention underneath the skin, but some of the causes we’ll talk about increase whole body water retention, including in that of the arteries. 

Let’s dive into the root causes of water retention. Some of these we can’t necessarily do anything about, but just the knowledge that they exist can keep your emotions calibrated during a fat loss phase. 

Root Causes of Water Retention

The first thing we have to understand is that whole body water balance is mainly determined by 3 different hormones, and then there’s a significant amount of upstream hormones and factors that can modify these root hormones, which can cause water retention. 

Not every cause of water retention works through these hormones, but many do, so let’s talk about the three hormones first, and then we’ll identify lifestyle factors and other hormones that modify levels of these. 

Antidiuretic hormone (ADH) 

Also known as vasopressin or arginine vasopressin, ADH is secreted by the posterior pituitary and acts at the level of the kidneys to reabsorb water back into circulation.

For a quick example, alcohol consumption inhibits the release of ADH, which is why you start peeing like nobody’s business after a couple drinks. 


Normally released in situations of low blood pressure or dehydration, aldosterone acts on the kidneys to increase sodium retention and facilitate potassium excretion. When more sodium is retained, it draws fluid with it, thereby causing water to be retained.

Atrial Natriuretic Peptide (ANP)

ANP does the opposite of aldosterone in some ways; when the heart senses higher atrial stretch than is necessary as well as high systemic blood pressure, it releases ANP which acts at the kidneys to increase their filtration rate as well as excrete sodium and water, which has the effect of decreasing blood pressure.  

Upstream Hormones and Factors Contributing

Chronic Stress/Chronically High Cortisol

When I say chronic stress, I’m referring to both physical stress and psychological stress combined; cortisol does not discriminate between the two. Dieting is part of this physical stress; even if the calorie level is appropriate, further into a diet and fat loss phase, we can easily get water retention. This is especially true though if calories are cut too hard, too soon. 

The Minnesota Starvation Experiment is a wonderful example of this. Ancel Keys led this particular study to look at the physiological effects of starvation. It involved 36 men over 6 months. The men were doing hard physical labor and had baseline expenditures of around 3200 calories. When the study began, they were cut to 1500 calories and maintained the routine of hard labor. 

During the first few months, researchers noted steady weight loss, usually about 2-4lb a week depending on the individual. After about 2 months however, weight loss became extremely non-linear; the researchers noted that all of the men’s scale weights would be stable for 1-3 weeks, and one morning they’d wake up and be many pounds lighter. 

This is the “whoosh effect” that anyone who’s dieted extensively will know very well. This occurred at random during the experiment, but always occurred after a high calorie meal.

For example, at the halfway point of the study, the researchers gave them a 2300 calorie meal in addition to their baseline daily calories (1500) as a kind of “celebration” to being halfway done, and everyone woke up 3-4 lb lighter the next morning. 

Anyone who’s been in a serious fat loss diet can relate to this. You’re dieting and it’s going well, but then all of the sudden you start to look worse and even jigglier than you were before. A refeed, or a day of much higher calories, usually causes the whoosh effect in this situation. 


As you’re dieting, you’re going to have steadily increasing levels of basal cortisol, as well as catecholamines (epinephrine and norepinephrine). Mechanistically, one of the things that’s causing the water retention in this situation is actually cortisol itself. Cortisol, in higher concentrations, can bind to the receptor that aldosterone normally does and cause sodium and fluid retention. 

Interestingly, in isolated test tube cell experiments, cortisol has been shown to inhibit ADH (the hormone that normally conserves water). 

However, in humans during conditions of psychological stress, both cortisol and ADH increase significantly. Remember, it’s ANTIdiuretic hormone, meaning if its low, it will cause water wasting, and if its high, it will cause water retention. 

Any situation where you have increased cortisol for longer periods of time, you might be retaining more water; another prominent example is if you’re getting consistently poor sleep.

Imbalances of Sodium and Potassium Consumption

While many mechanisms of water retention from the other causes are generated by increased retention of sodium at the kidney, it also makes sense that increasing the sodium that’s coming in relative to what you’re used to will also cause water retention.

There are many mechanisms behind this, so I’ll just detail a few. When you have a large amount of sodium in the interstitial fluid (space between the cells; usually what causes the jiggly-puffy look), it’s going to draw water with it. 

Your body does have a homeostatic set point with sodium consumption, meaning it gets used to whatever sodium level you’re taking in and minimizes water retention because of this. 

However, when you have a large bolus dose of sodium that exceeds the current homeostatic set point of salt balance in your body, in order to excrete the excess sodium, the kidneys concentrate it for excretion. 

How do you increase the concentration of a molecule in a liquid? By removing liquid; think about making a balsamic reduction.

The kidney reabsorbs significant amounts of water to concentrate sodium for excretion, leading to excess body water conservation until the excess sodium is out, after which it increases water excretion as well. 

This is mainly going to come into play with a sort of “cheat meal” or meal that is outside of your general plan that may have a big load of sodium that comes along with it. 

Excess Carbohydrate Leading to Higher Insulin 

Continuing on with the cheat meal example, chances are that the cheat meal had both a boatload of sodium which is going to influence water retention, but probably also a boatload of carbohydrate.

Carbohydrates can increase water retention by a few mechanisms. Firstly, just increase of intracellular fluid via glycogen storage; when carbohydrate is stored, its stored with water. 

Secondly, and probably the real culprit of the puffiness, is that the high insulin levels resulting from the large amount of carbohydrate will directly act at the kidney to increase sodium reabsorption. 

Chronic hyperinsulinemia or insulin resistance from excess calories and excess carbohydrate also increases the action of aldosterone at the kidneys, so you have a one-two punch of sodium retention, and therefore, water retention. 


When inflammation is present, the body releases histamine. Histamine causes the gaps between the cells of the capillary walls to widen. This is to make room for white blood cells to come in to fight any infection present. This is a normal process during acute injury and swelling. 

However, when you have systemic inflammation present, the same capillary wall widening can happen, even without the presence of white blood cells. When the capillary walls widen, inevitably a bit of fluid leaks out into the interstitial space, which can cause that puffy look. 

Other conditions that parallel systemic inflammation may also cause a one-two punch; metabolic syndrome for example. The hyperinsulinemia is causing sodium retention at the kidney level, plus the presence of systemic inflammation results in even more water retention. 

If you’ve had very overweight clients with significant metabolic syndrome or T2DM, you may have noticed that when they first started losing fat that the initial water drop during the first week or two was much larger than average. 


I’m sure all my females out there can relate to this one, particularly around that time of the month. Estrogen is a bit more interesting, because it mainly acts to lower the thermostat for when ADH releases. 

Normally ADH is secreted when plasma sodium reaches a certain level. As estrogen rises, it lowers the threshold of plasma sodium which ADH is released, and remember ADH conserves and retains body water. It also has a small effect on the renin-angiotensin system which contributes to water retention as well. 

Progesterone, on the other hand, acts as a natural diuretic, so when a woman has hormonal imbalances, mainly the common occurrence of high estrogen relative to progesterone, she’s going to experience significantly more water retention during certain times of her cycle than a woman with balanced hormones.

Combine this with the fact that when someone does have hormonal imbalances, this can make you biologically more reactive, emotionally speaking, and less resilient to psychological stress. That psychological stress can increase water retention via cortisol as well.

Supraphysiological levels of Testosterone and Other Anabolic Steroids

Testosterone in normal concentrations in the body won’t cause any excess water retention. It does have an influence on ADH, but the variations in men day to day are minimal and thus testosterone does not normally contribute to daily changes in body water.

This changes, however, when someone begins to use high levels of exogenous testosterone or other anabolic steroids.

Supraphysiological levels of many androgens can increase Renin-Angiotensin-Aldosterone System signaling and therefore aldosterone significantly, causing sodium retention. People using anabolic steroids are therefore going to be significantly more sensitive to changes in dietary sodium as far as body water retention goes. 

This can also contribute to the high blood pressure that some androgen users experience, and why many bodybuilders choose angiotensin receptor blockers (ARBs) like Telmisartan to combat this, since it directly targets the system that becomes hyperactive with androgen use. 

In addition to that, supraphysiological levels of androgens can also increase ADH, as I noted before. 

The last point to consider is that higher levels of testosterone will also mean higher levels of estrogen via aromatase, and as I discussed in the last point, estrogen has a greater influence on increasing ADH than even testosterone does. 

Supraphysiological levels of Growth Hormone

Supraphysiological levels of growth hormone can also cause significant amounts of water retention through two of the main hormones; it significantly increases both aldosterone and ADH. 

Most of the studies done to examine this were on patients with acromegaly, which is increased GH secretion through either a GH secreting tumor or another mechanism. 

Just know that if you’re choosing to use HGH as either a competitive drug or just for anti-aging purposes as you get older, this might come with a bit of water retention.

Not Drinking Enough Water

When your body senses that it’s low on fluid, it has many water conservation mechanisms in place. 

This involves all three of the hormones we previously mentioned. When the body senses low fluid, it’s going to increase aldosterone and ADH and decrease ANP, switching all the levers for increased fluid retention

The solution here is easy: Drink enough water! 


Finally, let’s address a list of medications that could also facilitate water retention (and make you frustrated on your fat loss journey):

  • Certain hormonal birth control preparations
  • Testosterone replacement therapy
  • NSAIDs
  • Calcium channel blockers (blood pressure medications – Amlodipine · Bepridil · Diltiazem)
  • Prednisone and other corticosteroids
  • Certain diabetes medications (Pioglitazone and rosiglitazone, as well as insulin therapy)

Integration and Conclusion

Water retention can be seriously frustrating, especially when it’s masking your hard-earned fat loss. Arming yourself with the knowledge of its causes, though, can really let you know exactly when you might be experiencing it, which can calm your mind and keep you on plan.

Many of these causes we can attempt to reverse engineer and deal with the root cause, such as excess sodium consumption, female hormonal imbalances, and inflammation, but others are going to be inevitable. You’ll just have to wait out the water retention from dieting heavily or consuming a cheat meal. 

The most important part is to not let it affect you too much psychologically while you’re on plan; remember to focus moreso on the 7-day daily averages of scale weight. If your weight went up 2-3 pounds overnight, its nearly guaranteed that it was just water weight fluctuation.  


Kojima S, Inoue I, Hirata Y, Saito F, Yoshida K, Abe H, Deguchi F, Kawano Y, Kimura G, Yoshimi H, et al. Effects of changes in dietary sodium intake and saline infusion on plasma atrial natriuretic peptide in hypertensive patients. Clin Exp Hypertens A. 1987;9(7):1243-58. doi: 10.3109/10641968709160047. PMID: 2957126.

Luft FC, Rankin LI, Bloch R, Willis LR, Fineberg NS, Weinberger MH. The effects of rapid saline infusion on sodium excretion, renal function, and blood pressure at different sodium intakes in man. Am J Kidney Dis. 1983 Jan;2(4):464-70. doi: 10.1016/s0272-6386(83)80079-1. PMID: 6823962.

Sagnella GA, Markandu ND, Buckley MG, Miller MA, Singer DR, MacGregor GA. Hormonal responses to gradual changes in dietary sodium intake in humans. Am J Physiol. 1989 Jun;256(6 Pt 2):R1171-5. doi: 10.1152/ajpregu.1989.256.6.R1171. PMID: 2525347.

Dugué B, Leppänen EA, Teppo AM, Fyhrquist F, Gräsbeck R. Effects of psychological stress on plasma interleukins-1 beta and 6, C-reactive protein, tumour necrosis factor alpha, anti-diuretic hormone and serum cortisol. Scand J Clin Lab Invest. 1993 Oct;53(6):555-61. PMID: 8266000.

Albåge A, van der Linden J, Bengtsson L, Lindblom D, Kennebäck G, Berglund H. Elevations in antidiuretic hormone and aldosterone as possible causes of fluid retention in the Maze procedure. Ann Thorac Surg. 2001 Jul;72(1):58-64. doi: 10.1016/s0003-4975(01)02688-1. PMID: 11465231.

Judith A. Whitworth, George J. Mangos, and John J. Kelly. Cushing, Cortisol, and Cardiovascular Disease. Originally published1 Nov 2000https://doi.org/10.1161/01.HYP.36.5.912Hypertension. 2000;36:912–916

S.G. Ruginsk et al. Central actions of glucocorticoids in the control of body fluid homeostasis: Review. • Braz J Med Biol Res 42 (1) • Jan 2009 • https://doi.org/10.1590/S0100-879X2009000100010

Espiner EA. The effects of stress on salt and water balance. Baillieres Clin Endocrinol Metab. 1987 May;1(2):375-90. doi: 10.1016/s0950-351x(87)80068-x. PMID: 3327497.

Rakova N, Kitada K, Lerchl K, Dahlmann A, Birukov A, Daub S, Kopp C, Pedchenko T, Zhang Y, Beck L, Johannes B, Marton A, Müller DN, Rauh M, Luft FC, Titze J. Increased salt consumption induces body water conservation and decreases fluid intake. J Clin Invest. 2017 May 1;127(5):1932-1943. doi: 10.1172/JCI88530. Epub 2017 Apr 17. PMID: 28414302; PMCID: PMC5409798.

Stachenfeld NS. Sex hormone effects on body fluid regulation. Exerc Sport Sci Rev. 2008 Jul;36(3):152-9. doi: 10.1097/JES.0b013e31817be928. PMID: 18580296; PMCID: PMC2849969.

Dimke H, Flyvbjerg A, Frische S. Acute and chronic effects of growth hormone on renal regulation of electrolyte and water homeostasis. Growth Horm IGF Res. 2007 Oct;17(5):353-68. doi: 10.1016/j.ghir.2007.04.008. Epub 2007 Jun 7. PMID: 17560155.

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