10 Reasons You Are Not Losing Weight on Intermittent Fasting

Article based on science

Learn little-known facts about why so many people are not losing weight with intermittent fasting.

After seeing one great result picture after the other, you might quickly get frustrated when not losing weight on intermittent fasting.

Instead of the beach body, you hit a plateau after the first pounds dropped initially.

But there’s no need to panic! Many people are not aware that the results of this supposedly simple diet can depend on tiny details.

However, I will explain them to you shortly so you can continue shedding pounds without effort. Therefore, we must start with the underlying mechanics of losing weight through intermittent fasting.

When Do You Start Losing Weight on Intermittent Fasting?

Fasting makes use of the fact that hormones control weight loss and gain. In short, the storage hormone insulin regulates body weight.

Accordingly, scientists can predict 75% of weight gain and loss in overweight people by analyzing their insulin levels (Kong et al. 20131).

Furthermore, insulin can block the enzyme, breaking down body fat (Meijssen et al. 20012).

Since fasting lowers insulin most effectively, it can have tremendous results. While fasting, the absence of food reduces insulin levels.

Your body prefers to tap into glycogen in the liver and muscles. Once these carbohydrate stores are empty, your body taps into stored fat for energy.

The fat-burning process is called ketosis and is a natural survival mechanism.

For this reason, the body builds fat reserves when food is abundant to tap into when it is scarce.

When your body burns stored fat for energy, you lose weight. But when you start losing weight through intermittent fasting is individual and heavily depends on your diet.

Hence, 16/8 intermittent fasting does not give you a free ticket for sweets during eating windows.

When starting fasting and your carbohydrate stores are complete, you will not lose a single gram of fat in the next 24 hours.

Because depending on your body, these stores can hold 1700-2200 calories. Thus, your glycogen stores cover your daily calorie requirements.

For this reason, intermittent fasting works best with the keto diet.

On keto, the body can start to burn fat after eating. Moreover, intensive exercise helps you get into ketosis faster by supporting glycogen stores’ depletion.

Whether you exercise, what and how much you eat, determines when you start losing weight. Besides, the body needs 3-6 weeks after a Standard American Diet to burn fat efficiently.

Why Am I Not Losing Weight on Intermittent Fasting?

If you strictly stick to your intermittent fasting schedule and still have problems shedding excess body fat, you might not be aware of some hidden factors.

However, if you cheat and sugar your tea or drink coffee with milk during fasting, don’t be surprised if you stall.

You must focus on your diet and scrutinize your lifestyle and routines to achieve your goals.

Let’s find out which subtle factors you are not losing weight on intermittent fasting.

1. You Reach for Processed Food

Also, with intermittent fasting, the focus is on fresh, natural food. Those who stick to industrial products from colorful packaging will hardly be successful.

Also, the fitness industry has become a mecca for shelf-stable foods.

Nevertheless, these industrially processed foods contain artificial colors, flavors, preservatives, and other additives that impede healthy metabolic function (Partridge et al. 20193; Hrncirova et al. 20194).

Moreover, it doesn’t matter if the label says “low-carb” or “vegan.”

Accordingly, added fiber is worthless and cannot dampen blood sugar and insulin spikes like fiber in natural food.

Hence, on intermittent fasting, fresh food paves the way to success. So take the time to prepare natural meals and exchange the protein bar for a free-range egg.

2. You Eat Too Many Carbohydrates

Even more important than the number of calories consumed is their quality.

Ultimately, being overweight is a hormonal rather than a caloric imbalance, as the world-famous neuroendocrinologist Dr. Robert Lustig concludes (Lustig 20015).

With this in mind, carbohydrates, in particular, stimulate insulin production and weight gain most strongly.

However, we should have eliminated some carbohydrates by crossing processed snacks and other convenience products off the shopping list.

But you don’t want to believe that cheap refined carbs are hiding everywhere—for example, vinegar, sauces, dressings, mustard, yogurt, etc.

Therefore I can only emphasize again and again that reading labels are mandatory. The food industry is exceptionally creative when it comes to names for sugar.

What ends up on -dextrin, -ose, -syrup, or -extract on the ingredients list is nothing but sugar.

Furthermore, it should be clear that starch is a polysaccharide. Therefore, potatoes, rice, corn, pasta, and bakery goods spike blood sugar and insulin levels.

Farmers use these foods to fatten livestock for a reason. They are a guarantee for weight gain.

Thus, exchanging these carbohydrates for healthy fats makes sense, which hardly raise insulin levels.

3. Your Meals Are Not Satiating

In contrast to carbohydrate-rich meals, fat-rich meals stimulate the release of satiety hormones much more strongly.

Hormones such as the peptide YY, GLP-1, or leptin send signals to the brain’s satiety center – the hypothalamus (Austin et al. 20096).

Ghrelin, on the other hand, is a hormone that signals hunger to the hypothalamus. Sugar, especially sweet fructose, stimulates ghrelin release (Teff et al. 20047).

That is why it is easy to overeat sweets, while pure fats are challenging for most people.

Accordingly, one study shows that even 5 hours after eating high-fat avocados, people are about 30% less hungry than after other meals (Wien et al. 20138).

Natural proteins also contribute significantly to satiety and need plenty of energy to be metabolized. However, humankind hasn’t known that proteins considerably stimulate insulin (Nuttall et al. 19919).

Therefore, simple low-carb approaches were doomed to fail.

For this reason, you should aim for a medium protein level to lose weight. An energy intake low in carbohydrates, moderate in protein, and rich in healthy fats is ideal for intermittent fasting.

The bottom line is a ketogenic diet that complements intermittent fasting best, not only because of how our body burns fat.

4. Your Veggies Are Full of Lectins

They are often dismissed as harmless, but the scientific burden of proof is overwhelming. Lectins come in countless variations, although you may have only heard of gluten so far.

Plants are not magically resistant to predators. Due to these sticky proteins, they are protected (Macedo et al. 201510).

Accordingly, lectins can bind to nerve endings in the gut and brain, which can cause inflammation and toxic reactions (Freed 199911).

The most crucial factor in weight loss is that they bind to insulin and leptin receptors and cause weight gain (Shechter 198312).

It is not without reason that lectin-containing foods such as wheat have repeatedly helped humanity build considerable fat reserves for winter.

Since vegetables containing lectin are the focus of industrial agriculture, they can be the well-hidden reason you are not losing weight on intermittent fasting.

As these vegetables are particularly resistant to parasites, they are the preferred varieties for cultivation. Typical suspects include widespread plant families:

  • Nightshades
    • Tomatoes
    • Potatoes
    • Eggplants
    • Chili
    • Peppers
    • Gojis
  • Cucurbits (including zucchinis and cucumbers)
  • Legumes (including peanuts and cashews)
  • Soy

Almost all grains and pseudo-grains, such as quinoa, contain lectins. However, these should not be on your menu if you want to lose weight seriously.

5. You Are Stressed

Stress is an essential factor people often overlook when weight loss stalls during intermittent fasting.

Nowadays, we are regularly exposed to psychological stressors, and the body releases cortisol more often than is healthy for us.

Cortisol is a steroid hormone crucial for stress reaction – the so-called fight or flight response.

Therefore, cortisol has been evolutionarily essential to prepare the body for fight or flight. For example, to escape the threat of a predator.

After cortisol is released, it increases blood sugar levels. The mobilized energy aims to strengthen the muscles and eventually flee and survive (Owen et. al 197313).

The increased blood sugar, in turn, results in an elevated insulin level. Therefore stress directly counteracts the weight loss effect of intermittent fasting.

Besides, it limits metabolic functions such as digestion to focus on surviving.

As permanent stress constantly stimulates insulin secretion, it contributes to weight gain, insulin resistance, and type 2 diabetes (Rizza et al. 198214).

Furthermore, the fat storage enzyme 11 beta-hydroxysteroid dehydrogenase-1 (HSD) can reactivate inactive cortisol stored in belly fat.

As a result, fat storage within these abdominal cells is stimulated (Ayachi et al. 200615).

6. You Are Lacking Sleep

Probably the most effective way to counteract stress is to get enough sleep. Conversely, lack of sleep is one of the most significant stressors.

However, about one-third of all working adults now get less than six hours of sleep every night.

In this context, a sleep deprivation and obesity meta-analysis show that less than six hours of sleep increases the risk of weight gain by a whopping 50 percent (Cappuccio et al. 200816).

Lack of sleep affects your hormones. For example, it elevates cortisol and ghrelin while lowering leptin levels.

The bottom line is that this sets a vicious circle in motion. While more ghrelin and less leptin trigger increased appetite, cortisol promotes fat storage via insulin (Taheri et al. 200417).

If you get less than eight hours of sleep a day, you have just found a significant reason you are not losing weight on intermittent fasting.

7. You Are Exercising Excessively

Like too little sleep, too much exercise can also stress the body. You can get too much of a good thing, after all.

There is also a healthy limit to working out. Because exercise is still advertised as the panacea that can magically nullify poor diet choices, people often exceed the healthy limit.

Although exercise is crucial for mental health, diet is the basis for sustainable weight loss.

The most common form of exaggeration is by doing endurance training. And it is precisely this that activates compensatory mechanisms. Those who run a lot will eat a lot.

The exponentially increasing appetite is something I had to witness repeatedly during marathon preparation, in which I always put on weight.

The body reclaims its energy and wants to prepare for more intense energy consumption. As biology demands it emphatically, you will also overeat if you overdo endurance training.

While healthy training causes acute inflammation, excessive exercise can cause chronic inflammation and stress (Hackney 200618).

8. You Drink Hidden Calories

A sports drink after working out and an organic lunch juice are healthy, aren’t they?

Well, not so fast.

Drinks are one of the most common reasons why are not losing weight. No matter how keto your diet is, you’ll still put on weight with these liquid meals.

You must avoid sugary drinks such as soda and juices at all costs.

When you remove the protective dietary fiber from fruits, which are already full of sugar, the blood sugar and insulin will skyrocket.

You can also overdo it with supposedly healthy things. If you drink every coffee with organic cream or grass-fed butter, this consumed energy will add up throughout the day.

A Bulletproof Coffee makes sense if it helps you stay full longer without needing a meal during fasting. After all, you want to burn your body fat instead.

The cornerstones of intermittent fasting are water, tea, and coffee without additives. This way, you prevent calories from entering your body while staying hydrated, which prevents headaches during fasting.

Finally, you must pay attention to the label of all other drinks. Spoiler: Thereby, alleged weight loss drinks often come out as fattening.

9. You Binge on Sweeteners

Sugar-free zero and diet drinks have always been trendy. Nevertheless, these products make people reach a plateau on intermittent fasting repeatedly.

Does Zero sugar equal full-fat burning, as the advertising teaches us? Unfortunately, the reality looks quite different.

Although sweeteners such as aspartame and stevia do not increase blood sugar levels, they also release insulin (Anton et al. 201019).

Moreover, they eradicate gut bacteria that contribute significantly to our health (Ruiz-Ojeda und Plaza-Díaz 201920).

Even if sweeteners do not cause the blood sugar to surge, they make us hungry for more. More precisely, diet drinks stimulate the craving for sweets more than drinks containing conventional sugar (Yang 201021).

Not only does it seem that people who consume light products like water are more often overweight. That’s a proven fact.

Accordingly, researchers at the University of Texas at San Antonio found that the probability of weight gain from consuming diet soda increases by 47 percent (Fowler et al. 200822).

Due to zero drinks, many people are not losing weight on intermittent fasting. Don’t be one of them.

10. Your Body Lacks Salt

The image of salt has been so bad over decades that few people realize that we cannot live without sodium.

Contrary to all fears, citizens of the countries with the highest salt consumption also have the fewest cardiovascular diseases (Park et al. 201623).

Moreover, salt is the natural antagonist of sugar and counteracts cravings.

In contrast to sugar, salt also has a positive feedback loop. When your body has had enough salt, you don’t feel like it anymore.

While sugar consumption promotes insulin resistance and body fat storage, salt increases insulin sensitivity and helps you lose weight (Sakuyama et al. 201624).

Especially on intermittent fasting, salt is a must. If you get a headache, feel tired, or nauseous, it is probably due to a sodium deficiency.

When emptying the glycogen stores during fasting, the body flushes out considerable amounts of liquid and electrolytes, especially sodium. Moreover, this is the leading cause of most physical complaints while intermittent fasting.

High-quality salts such as pink Himalaya, Celtic sea salt, or bone broth can remedy electrolyte deficiency.

Why Am I Not Losing Weight on Intermittent Fasting and Keto?

A ketogenic diet gives you an almost unfair advantage. Things get tricky if you can’t lose weight despite keto and intermittent fasting.

However, your body is not a weight loss machine that can permanently lose weight. Having that said, stagnation could also have the following reasons:

  • Initial weight loss: At the beginning of the intermittent fasting, you lost a lot of weight in the form of water retention, and now you wonder why it does not continue at the same pace
  • Approaching target weight: Weight loss will slow down if you have already lost significant weight. The closer you reach your target weight, the more you experience a weight loss stall.
  • Thyroid problems: If you have reached this point, you may experience thyroid or adrenal gland issues and immediately contact your doctor.

If you still do not know why you cannot lose weight despite intermittent fasting, I recommend reading points 4) and 9) again.

Unfortunately, they are often played down or ignored.

The Bottom Line

You don’t have to worry if you have just hit a plateau for the first time during intermittent fasting. There are proper reasons for the situation as individual as your body.

To find out how your unique body reacts to distinctive foods and habits, you need cautious trial and error while listening to it.

However, the best way to start is to go through the above list and pick out the causes most likely to apply.

Frequently Asked Questions (FAQ)

Why am I not losing weight on intermittent fasting?

Reasons for not losing weight on intermittent fasting are lack of sleep, hidden carbs, artificial sweeteners, and many more you can find in this article.

How long does it take to start losing weight on intermittent fasting?

You will experience initial weight loss within a week when the body’s water depots are depleting. Besides, your body may need 3-6 weeks to adapt to fat-burning efficiently.

Why am I gaining weight with intermittent fasting?

You might overeat on poor food choices when breaking the fast. For more subtle reasons, read this article.

How do I break my weight loss plateau on intermittent fasting?

Often, subtle nuances of everyday life are the reason why weight loss stalls. Pay attention to sleep patterns, stress levels, and labels on the food you buy to break your weight loss plateau on intermittent fasting.



1Kong LC, Wuillemin PH, Bastard JP, Sokolovska N, Gougis S, Fellahi S, Darakhshan F, Bonnefont-Rousselot D, Bittar R, Doré J, Zucker JD, Clément K, Rizkalla S. Insulin resistance and inflammation predict kinetic body weight changes in response to dietary weight loss and maintenance in overweight and obese subjects by using a Bayesian network approach. Am J Clin Nutr. 2013 Dec;98(6):1385-94. doi: 10.3945/ajcn.113.058099. Epub 2013 Oct 30. PubMed PMID: 24172304.

2Meijssen S, Cabezas MC, Ballieux CG, Derksen RJ, Bilecen S, Erkelens DW. Insulin mediated inhibition of hormone sensitive lipase activity in vivo in relation to endogenous catecholamines in healthy subjects. J Clin Endocrinol Metab. 2001 Sep;86(9):4193-7. doi: 10.1210/jcem.86.9.7794. PubMed PMID: 11549649.

3Partridge D, Lloyd KA, Rhodes JM, Walker AW, Johnstone AM, Campbell BJ. Food additives: Assessing the impact of exposure to permitted emulsifiers on bowel and metabolic health – introducing the FADiets study. Nutr Bull. 2019 Dec;44(4):329-349. doi: 10.1111/nbu.12408. Epub 2019 Nov 25. PubMed PMID: 31866761; PubMed Central PMCID: PMC6899614.

4Hrncirova L, Hudcovic T, Sukova E, Machova V, Trckova E, Krejsek J, Hrncir T. Human gut microbes are susceptible to antimicrobial food additives in vitro. Folia Microbiol (Praha). 2019 Jul;64(4):497-508. doi: 10.1007/s12223-018-00674-z. Epub 2019 Jan 17. PubMed PMID: 30656592.

5Lustig RH. The neuroendocrinology of childhood obesity. Pediatr Clin North Am. 2001 Aug;48(4):909-30. doi: 10.1016/s0031-3955(05)70348-5. Review. PubMed PMID: 11494643.

6Austin J, Marks D. Hormonal regulators of appetite. Int J Pediatr Endocrinol. 2009;2009:141753. doi: 10.1155/2009/141753. Epub 2008 Dec 3. PubMed PMID: 19946401; PubMed Central PMCID: PMC2777281.

7Teff KL, Elliott SS, Tschöp M, Kieffer TJ, Rader D, Heiman M, Townsend RR, Keim NL, D’Alessio D, Havel PJ. Dietary fructose reduces circulating insulin and leptin, attenuates postprandial suppression of ghrelin, and increases triglycerides in women. J Clin Endocrinol Metab. 2004 Jun;89(6):2963-72. doi: 10.1210/jc.2003-031855. PubMed PMID: 15181085.


8Wien M, Haddad E, Oda K, Sabaté J. A randomized 3×3 crossover study to evaluate the effect of Hass avocado intake on post-ingestive satiety, glucose and insulin levels, and subsequent energy intake in overweight adults. Nutr J. 2013 Nov 27;12:155. doi: 10.1186/1475-2891-12-155. PubMed PMID: 24279738; PubMed Central PMCID: PMC4222592.

9Nuttall FQ, Gannon MC. Plasma glucose and insulin response to macronutrients in nondiabetic and NIDDM subjects. Diabetes Care. 1991 Sep;14(9):824-38. doi: 10.2337/diacare.14.9.824. Review. PubMed PMID: 1959475.

10Macedo ML, Oliveira CF, Oliveira CT. Insecticidal activity of plant lectins and potential application in crop protection. Molecules. 2015 Jan 27;20(2):2014-33. doi: 10.3390/molecules20022014. Review. PubMed PMID: 25633332; PubMed Central PMCID: PMC6272522.

11Freed DL. Do dietary lectins cause disease?. BMJ. 1999 Apr 17;318(7190):1023-4. doi: 10.1136/bmj.318.7190.1023. PubMed PMID: 10205084; PubMed Central PMCID: PMC1115436.

12Shechter Y. Bound lectins that mimic insulin produce persistent insulin-like activities. Endocrinology. 1983 Dec;113(6):1921-6. doi: 10.1210/endo-113-6-1921. PubMed PMID: 6357762.

13Owen OE, Cahill GF Jr. Metabolic effects of exogenous glucocorticoids in fasted man. J Clin Invest. 1973 Oct;52(10):2596-605. doi: 10.1172/JCI107452. PubMed PMID: 4729053; PubMed Central PMCID: PMC302520.

14Rizza RA, Mandarino LJ, Gerich JE. Cortisol-induced insulin resistance in man: impaired suppression of glucose production and stimulation of glucose utilization due to a postreceptor detect of insulin action. J Clin Endocrinol Metab. 1982 Jan;54(1):131-8. doi: 10.1210/jcem-54-1-131. PubMed PMID: 7033265.

15Ayachi SE, Paulmyer-Lacroix O, Verdier M, Alessi MC, Dutour A, Grino M. 11beta-Hydroxysteroid dehydrogenase type 1-driven cortisone reactivation regulates plasminogen activator inhibitor type 1 in adipose tissue of obese women. J Thromb Haemost. 2006 Mar;4(3):621-7. doi: 10.1111/j.1538-7836.2006.01811.x. PubMed PMID: 16460444.

16Cappuccio FP, Taggart FM, Kandala NB, Currie A, Peile E, Stranges S, Miller MA. Meta-analysis of short sleep duration and obesity in children and adults. Sleep. 2008 May;31(5):619-26. doi: 10.1093/sleep/31.5.619. PubMed PMID: 18517032; PubMed Central PMCID: PMC2398753.


17Taheri S, Lin L, Austin D, Young T, Mignot E. Short sleep duration is associated with reduced leptin, elevated ghrelin, and increased body mass index. PLoS Med. 2004 Dec;1(3):e62. doi: 10.1371/journal.pmed.0010062. Epub 2004 Dec 7. PubMed PMID: 15602591; PubMed Central PMCID: PMC535701.

18Hackney AC. Stress and the neuroendocrine system: the role of exercise as a stressor and modifier of stress. Expert Rev Endocrinol Metab. 2006 Nov 1;1(6):783-792. doi: 10.1586/17446651.1.6.783. PubMed PMID: 20948580; PubMed Central PMCID: PMC2953272.

19Anton SD, Martin CK, Han H, Coulon S, Cefalu WT, Geiselman P, Williamson DA. Effects of stevia, aspartame, and sucrose on food intake, satiety, and postprandial glucose and insulin levels. Appetite. 2010 Aug;55(1):37-43. doi: 10.1016/j.appet.2010.03.009. Epub 2010 Mar 18. PubMed PMID: 20303371; PubMed Central PMCID: PMC2900484.

20Ruiz-Ojeda FJ, Plaza-Díaz J, Sáez-Lara MJ, Gil A. Effects of Sweeteners on the Gut Microbiota: A Review of Experimental Studies and Clinical Trials. Adv Nutr. 2019 Jan 1;10(suppl_1):S31-S48. doi: 10.1093/advances/nmy037. PubMed PMID: 30721958; PubMed Central PMCID: PMC6363527.

21Yang Q. Gain weight by “going diet?” Artificial sweeteners and the neurobiology of sugar cravings: Neuroscience 2010. Yale J Biol Med. 2010 Jun;83(2):101-8. Review. PubMed PMID: 20589192; PubMed Central PMCID: PMC2892765

22Fowler SP, Williams K, Resendez RG, Hunt KJ, Hazuda HP, Stern MP. Fueling the obesity epidemic? Artificially sweetened beverage use and long-term weight gain. Obesity (Silver Spring). 2008 Aug;16(8):1894-900. doi: 10.1038/oby.2008.284. Epub 2008 Jun 5. PubMed PMID: 18535548.


23Park J, Kwock CK, Yang YJ. The Effect of the Sodium to Potassium Ratio on Hypertension Prevalence: A Propensity Score Matching Approach. Nutrients. 2016 Aug 6;8(8). doi: 10.3390/nu8080482. PubMed PMID: 27509520; PubMed Central PMCID: PMC4997395.

24Sakuyama H, Katoh M, Wakabayashi H, Zulli A, Kruzliak P, Uehara Y. Influence of gestational salt restriction in fetal growth and in development of diseases in adulthood. J Biomed Sci. 2016 Jan 20;23:12. doi: 10.1186/s12929-016-0233-8. Review. PubMed PMID: 26787358; PubMed Central PMCID: PMC4719732.

Mag. Stephan Lederer, MSc. is an author and blogger from Austria who writes in-depth content about health and nutrition. His book series on Interval Fasting landed #1 on the bestseller list in the German Amazon marketplace in 15 categories.

Stephan is a true man of science, having earned multiple diplomas and master's degrees in various fields. He has made it his mission to bridge the gap between conventional wisdom and scientific knowledge. He precisely reviews the content and sources of this blog for currency and accuracy.

Click on the links above to visit his author and about me pages.

Leave a Reply