Have you ever wondered why, after a sugary drink or sweet dish, you found yourself craving ‘just one more’? This sounds like a reality for many individuals. Sugar is an integral part of our day-to-day lives, whether it’s in morning tea, breakfast cereals, snacks wrapped in foil, or after-dinner desserts. This might be the reason why a “30-day no added sugar challenge” has gained such popularity in the wellness world.
But what really happens inside our brain when we cut out that added sugar? Does our dopamine spike? Can we overcome our cravings? Do we feel happier, and does our focus improve? The truth is a bit more complicated than a straightforward ‘sugar detox’ suggests. Research indicates that reducing added sugar may help to encourage healthy eating habits and improve metabolic health. Its direct impact on our moods and cognitive abilities is still under investigation (Gillespie et al., 2024; World Health Organisation [WHO], 2023).
Read More: The Psychology Behind Sugar Cravings: Why Sugar Feels So Addictive to the Brain
What Actually Counts as ‘Added Sugar’?
While fantasising about free-added-sugar day trips, people should understand the meaning of ‘added sugar ’, which is different from naturally sweet ones. Added sugars are those in which sugar is added to food products and drinks during manufacturing and preparation. This would include different types of syrups and other forms of sugar contained in candies, snacks, soft beverages, savory sauces.
There is an even further expanded terminology which is used by WHO: “free sugars,” which include naturally occurring sweet items such as honey, syrup and fruit juices (WHO, 2015). This does not mean people need to eliminate carbohydrates or cut back on fruit that would include apples and bananas. The human brain functions on a large amount of glucose for energy, and that is acquired through a variety of carbohydrate-rich foods other than sweetened food items like chocolates, sodas, etc. (Dienel, 2019).
Sugar and the Brain’s Reward System
Sweet foods are more than just pleasant in taste. They directly stimulate the brain’s reward and motivational systems. Highly palatable foods can activate the mesolimbic reward pathway, which encompasses brain areas like the ventral tegmental area and the nucleus accumbens. The neurotransmitter dopamine plays a crucial role in reinforcing behaviours, prompting motivation, and helping in learning through the reward system (Avena et al., 2008). It is crucial to understand that eating a chocolate bar doesn’t cause a dopamine ‘high’ equivalent to taking an addictive drug.
Food and drugs interact differently with reward pathways, and so far, the evidence regarding sugar’s addictive potential in humans is still quite limited (Westwater et al., 2016). Interestingly, a study involving people that looked at the effects of consuming a sugary drink every day for three weeks found changes in activity within certain parts of the brain’s reward pathways (Burger & Stice, 2017). While these findings suggest that repetitive consumption of highly palatable foods could alter responses within the reward system, it does not definitively prove that sugar on its own leads to addiction.
Read More: Why Do We Eat What We Eat? Understanding the Psychology Behind Food Choices
What Is Likely To Happen Over The 30 Days?
Over time, limiting intake of added sugar may change the way people relate to sweetness, reward systems, and habits. When someone consistently reaches for sugary snacks after having lunch, they might initially anticipate a reward because his/her brain has established an association with the time of day, setting, and expected pleasure. Through regular exposure without that promised reward, the learned connection may weaken. However, this process can significantly vary from person to person. Sleep, stress, the foods individuals consume, their eating routines, and even emotional connections to certain foods all play a role in shaping how they experience cravings.
1. Days 1-7: The “Withdrawal” and Cravings begin
This first week is usually the toughest for individuals who tend to consume large amounts of sugary products. Cravings may appear strongly at particular familiar times, such as a desire for a sweet drink during the afternoon slump. Some people report experiencing headaches, fatigue, irritability, or difficulty focusing after significantly reducing sugar. These effects are sometimes called “sugar withdrawal.”
It’s important to emphasise that researchers generally advise not to compare these withdrawal symptoms with clinically diagnosed drug addiction. Reviews of current literature studies involving humans found insufficient evidence to categorise sugar as an addictive agent (Westwater et al., 2016). Therefore, feeling discomfort in the initial phase of a challenge may be due to a combination of the following:
- Changes in habit and conditioned cravings
- Fluctuations in total calorie and carbohydrate consumption
- Hunger due to an inability to adequately replace the foods individuals cut out
- One’s own expectations related to taking part in the challenge
- Adjustments if someone removed caffeine along with sweetened beverages and coffee
- General adaptation in eating less-sweetened items.
In essence, discomfort is not proof of the brain ‘detoxifying.’
2. Days 8-14: Cravings and Appetite may start to shift
Once people start to adapt to a different routine, some individuals may find that the frequency or intensity of their cravings begins to decrease. Part of this effect is behavioural: their brain eventually learns to weaken the association between a trigger event and the anticipated outcome when that reward isn’t delivered.
Studies conducted on low-sugar intake reveal distinct impacts on both appetite and cravings, which vary depending on food composition and individual differences (SWEET Consortium, 2024). When evaluating sugar-reduced diets, researchers often observe an initial surge in intense sugar cravings and irregular hunger pangs, followed by a gradual stabilisation of overall appetite. It is important to distinguish between these two experiences, as they are driven by entirely different brain mechanisms:
- Appetite (The Homeostatic System): Appetite is the physiological need for food, primarily regulated by the hypothalamus. This brain region monitors energy needs by balancing hunger hormones (ghrelin) and satiety hormones (leptin). Reducing sugar intake forces the hypothalamus to adapt, which can initially cause fluctuating hunger levels before ultimately improving the body’s natural satiety signalling so you feel fuller longer.
- Cravings (The Hedonic Reward System): Cravings represent an intense psychological desire for specific foods, governed by the mesolimbic dopamine pathway. Because sugar triggers significant dopamine release, sudden restriction causes a temporary dopamine deficit, manifesting as intense withdrawal-like urges for sweets. However, sustained sugar reduction allows dopamine receptors to recalibrate, eventually diminishing the frequency and intensity of these cravings over time.
3. Days 15-21: Energy levels and mood-more complex than people think
One of the commonly reported benefits of reducing sugar for 30 days is a noticeable surge in energy and a dramatic improvement in mood. However, this isn’t always the case. Cutting out foods high in added sugar can improve overall dietary quality if someone is replacing them with a good, balanced range of foods. There is evidence of a link between sugar consumption and depression.
A meta-analysis of observational studies involving more than 365,000 participants showed that eating sugary beverages regularly was associated with a slightly higher risk of depression, although these studies could not prove that sugar caused depression (Hu et al., 2019). As a result, increased energy and a better mood after stop eating added-sugars may be a consequence of multiple changes occurring together – better dietary quality, more consistent eating, weight loss, improved sleep quality, or reduced consumption of highly processed foods.
4. Days 22-30: What about memory and concentration?
“Will a month of added-sugar elimination make individuals smarter or better memory?” This is where people don’t get concrete answers. After a meta-analysis of 77 studies focusing on free added sugar in humans’ cognitive ability, they got mixed results. The evidence showed that short-term glucose gave benefits under fasting conditions, yet in the long term, higher intake of sugar led to a higher risk of cognitive impairment.
The conclusion is that the sugar people take for granted is not the issue; the issue lies in the sugar people add (Gillespie et al., 2024). People must remember that their brain needs glucose to function, but that doesn’t mean it needs the sugar they add. Glucose can be produced from carbohydrates in ordinary meals, and the body has sophisticated mechanisms for maintaining blood glucose availability (Dienel, 2019). Eliminating added sugar for 30 days should not be expected to suddenly produce sharper memory or extraordinary concentration.
Read More: Sweet Trap: How High Sugar Diets Affect a Child’s Brain
The Big Picture: More Healthy Foods, Less Sugary Fear
The best perspective of a month-long challenge without sugar is not “sugar is bad”, but instead an opportunity to reflect on how and when someone usually eats sugary treats. One possible healthy approach could be to substitute sugary beverages for water and tea without sweeteners, go for fresh fruit instead of processed sweet desserts, or read food labels and structure meals around fibre-rich carbohydrates, protein, and healthy fats.
Remember, it’s not scientific to eliminate naturally occurring sugars found in fruit and vegetables (WHO, 2015). Most importantly, people are trying to foster enjoyment and not guilt in their food. Healthy eating does not mean individuals can never have a sugary treat once in a while; it means ensuring the intake of added sugars fits within limits and their overall diet is well-balanced.
Conclusion
While a month of eliminating added sugar is unlikely to miraculously ‘reset’ the brain as social media may suggest, it can be revealing in a more fundamental way: how habits, reward systems, environmental cues, and food preferences significantly influence people’s daily life food choices. However, there’s still no agreement on the topic of sugar withdrawal, increased brain sensitivity to dopamine, or any measurable improvements in human cognitive functions (Westwater et al., 2016; Gillespie et al., 2024).
Nevertheless, decreasing the intake of added sugar as part of diet is a positive health goal. This is especially true if someone is replacing those sugary items with whole, nutritious foods rather than just skipping them. Ultimately, the goal isn’t to create a guilt-ridden relationship with sugar. It isn’t to build a perfect brain that remains totally unaffected by the pleasure of something sweet. Instead, the goal is to cultivate the ability to choose sweetness rather than rely on it all the time. A 30-day challenge may not reset the brain. But it can surely change the relationship with one’s food habits in the best possible ways.
References +
- Avena, N. M., Rada, P., & Hoebel, B. G. (2008). Evidence for sugar addiction: Behavioural and neurochemical effects of intermittent, excessive sugar intake. Neuroscience & Biobehavioral Reviews, 32(1), 20–39. https://doi.org/10.1016/j.neubiorev.2007.04.019
- Burger, K. S., & Stice, E. (2017). Frequent ice cream consumption is associated with reduced striatal response to receipt of an ice cream-based milkshake. American Journal of Clinical Nutrition, 106(1), 1–8.
- Dienel, G. A. (2019). Brain glucose metabolism: Integration of energetics with function. Physiological Reviews, 99(1), 949–1045. https://doi.org/10.1152/physrev.00062.2017
- Gillespie, K. M., White, M. J., & Kemps, E. (2024). The impact of free and added sugars on cognitive function: A systematic review and meta-analysis. Nutrients, 16(1), 75. https://doi.org/10.3390/nu16010075
- Hu, D., Cheng, W., & Tu, Y. (2019). Sugar-sweetened beverages consumption and the risk of depression: A meta-analysis of observational studies. Journal of Affective Disorders, 245, 348–355.
- SWEET Consortium. (2024). Acute and two-week effects of neotame, stevia rebaudioside M and sucrose-sweetened biscuits on postprandial appetite and endocrine response in adults with overweight/obesity: A randomised crossover trial. Appetite, 195, 107871.
- Westwater, M. L., Fletcher, P. C., & Ziauddeen, H. (2016). Sugar addiction: The state of the science. European Journal of Nutrition, 55(2), 55–69.
- World Health Organisation. (2015). Guideline: Sugar intake for adults and children. World Health Organisation.
- World Health Organisation. (2023). Carbohydrate intake for adults and children: WHO guideline. World Health Organisation.
- World Health Organisation. (2023). Healthy diet. World Health Organisation.
