While fads in diet come and go, the low-carb trend has maintained a firm hold on the global health and wellness industry. Introduced as early as the 1860s, the method regained popularity during the 1970s in the form of the Atkins diet and again with the more recent paleo and keto dieting. The overall idea has remained mostly the same: reduce carbs to shed pounds and experience metabolic benefits.

But what really happens in your body when you cut carbs completely out — even temporarily, like a week? An increasing number of individuals are giving temporary carb deprivation a try, wanting to learn how their body reacts. The outcome, however, is far more complex than expected.

What Are Carbohydrates?

Carbohydrates are one of the three macronutrients necessary — in addition to protein and fat — for the human body to function and be healthy in large quantities. Healthy adults, the 2020–2025 Dietary Guidelines for Americans recommend, need to consume between 45% to 65% of their daily calories from carbohydrates. These are fruits, vegetables, legumes, whole grains, and dairy — foods that also contain fiber, vitamins, and important minerals.

Notably, the body cannot produce carbohydrates by itself. That is, they have to be derived from diet. So what occurs when you defy this biological makeup?

Nutritionist Justin Gichaba went on social media platform Instagram, he started the challenge of eliminating all carbs for seven days and shared his experience on social media. His test revealed both the famous and lesser-known impacts of zero-carb living.

"I felt lighter, less bloated, and more mentally clear," Gichaba said. These short-term effects are typically reported by those who adopt low-carb diets. In fact, lower carbohydrate consumption can actually help to reduce water retention and normalize blood sugar first, which could result in greater alertness and less brain fog.

Yet the advantages had boundaries. "My workouts were horrible," Gichaba admitted. "I had no energy, and my performance was awful." Without carbs, he found strength training and endurance during cardio a challenge.

Why Energy Levels Take a Dip?

Carbohydrates are the body's first choice as a source of rapid energy — especially useful in physical activity. When you drop carbs, however, your body resorts to using fat for energy, going into a metabolic stage called ketosis. Although ketosis can work for weight reduction, it hurts many at the expense of weakness, decreased stamina, and recovery.

Carbs also help shuttle the body into rest and recovery mode after exercise. Without them, stress hormones can remain elevated longer, increasing fatigue and delaying muscle repair.

As your brain primarily runs on glucose (a simple carbohydrate), depriving it of its favorite fuel source can lead to cognitive side effects. People often report feeling mentally sluggish or irritable in the first several days of carb elimination.

In the early phases of ketosis, dizziness, headaches, and weakness are also experienced. These are the reactions to the metabolic change as the body learns to make ketones rather than utilizing glucose.

How Does No Carbs Affect The Body?

Another underappreciated effect of steering clear of carbs is a tremendous decrease in fiber intake, prevalent in whole foods like whole grains, fruits, legumes, and vegetables. Fiber is imperative in aiding digestion, ensuring daily bowel movements, and nourishing beneficial gut flora.

Without fiber, most individuals on zero-carb diets are plagued by constipation, bloating, or gut dysbiosis — complications that can remain or intensify with long-term restriction.

While short-term carb restriction can facilitate rapid weight loss, studies indicate that long-term compliance with very low-carb diets can be detrimental to health. A 2022 study in Current Developments in Nutrition reported that some participants on low-carb diets had a rise in LDL (bad) cholesterol, most likely because of lower fiber and higher saturated fat consumption.

Other long-term hazards can include kidney stress, bone loss of density, and decreased physical function, although evidence is conflicting. Population studies have also found a correlation between very low-carbohydrate diets and increased all-cause mortality, although causation has yet to be determined.

Completely eliminating carbohydrates is not only nutritionally unbalanced but frequently unsustainable. Omitting one food group can result in deficiencies and enhance the risk of disordered eating behavior.

Rather, quality over quantity is recommended by experts. Not all carbohydrates are equal — leafy greens, sweet potatoes, berries, and legumes are rich in nutrients that maintain long-term health. Steer clear of ultra-processed, sugary carbs and not all carbs in general.

Should You Go Carb-Free?

For the average healthy person, the drawbacks of eliminating carbs outweigh any benefits — particularly in the long run. Carbohydrates play a role in brain function, digestion, muscle function, and hormonal balance. If you do want to use a low-carb diet for particular health issues, talk with a health care provider or registered dietitian so that it is done safely and in a sustainable way.

A week of going carb-free can be a fun experiment, but it should not become a way of life without precise medical advice. The smarter option? Focus on whole-food, complex carbs and keep nutrition balanced.

You’ve seen it on your Instagram feed, heard your gym buddy rave about it, maybe even tried it yourself to drop those stubborn pounds. Cutting carbs, loading up on fats, watching the scale tip in your favor—it all sounds like magic, right? And within weeks your jeans fit better. The ketogenic diet, once a niche medical treatment, has exploded into a mainstream weight-loss trend. From celebrities to fitness enthusiasts, people across the globe have adopted keto for its promise of quick weight loss and better energy. But beneath the headlines and transformation posts lies a more complex reality—especially when it comes to your internal health.

But here’s the thing, behind the dramatic before-and-after photos and bulletproof coffee obsession, there’s a whole lot more happening inside your body than just fat burning. What does this ultra-low-carb lifestyle really mean for your gut, heart, brain, skin, liver, and kidneys? Is it a metabolic makeover—or are there trade-offs we’re not talking about enough?

We asked top experts to weigh in, and their answers may surprise you because while keto might help you slim down in the short run, your organs could be telling a very different story in the long haul.

The keto diet fundamentally shifts how your body generates energy. "By cutting carbs drastically, the body enters ketosis, burning fat for fuel instead of glucose," says Dietician Drishya Ale. Initially, the weight loss is mostly water due to lowered insulin and glycogen stores. But this carb-cut also means cutting out most fiber-rich foods—fruits, legumes, and whole grains.

"That can lead to constipation and disrupt your gut microbiota," she says. Add to that a spike in fat intake—often difficult to digest for some—and you get bloating or discomfort. While some people eventually report more energy and reduced appetite, others struggle with fatigue and vitamin deficiencies.

Drishya’s says, "Not all keto is the same. A clean keto approach with whole foods is a far cry from one loaded with processed meats and saturated fats."

Heart

Dr. Neerav Bansal, Cardio Thoracic Vascular Surgeon, "Keto may improve some heart markers in the short term—like lowering insulin, blood sugar, and triglycerides," says Dr. Neerav Bansal. But it’s not a one-size-fits-all fix.

Some people may experience a rise in LDL (bad cholesterol), especially if their keto is heavy in saturated fats from red meat and full-fat dairy. "This is particularly risky for those with a personal or family history of heart disease," he cautions.

In the long term, the heart health effects depend on the quality of fats consumed. Unsaturated fats from avocados, nuts, and olive oil can support heart health, while overloading on processed food and saturated fat can do damage.

Dr. Bansal emphasizes moderation, regular monitoring of cholesterol, and a personalized approach tailored to individual health profiles.

Brain

"The brain loves ketones, ketones, produced during ketosis, may be a more efficient energy source for the brain than glucose. For some, this translates to better focus, memory, and mental clarity," explains Dr. Mahesh Gour, Memory Coach, Cognitive Expert

There's research suggesting keto reduces brain inflammation and oxidative stress, which are linked to cognitive decline. That’s why keto is being explored for conditions like epilepsy, Alzheimer’s, and Parkinson’s.

But Dr. Gour warns, “If not properly managed, long-term keto can cause nutrient shortages and even affect mood or serotonin levels.” In other words, the same diet that sharpens your focus could also dull it, if not followed wisely.

Skin and Hair

However, it’s not all glow. "In early phases, some experience keto rash, and temporary hair loss due to stress on hair follicles," she notes. Over time, poor nutrition—especially lacking vitamins A, C, E, biotin, and zinc—can lead to dull skin and thinning hair.

Follow a nutrient-rich keto plan and supplement when necessary. Also, avoid overdoing saturated fats, which can clog pores and trigger breakouts in some.

Liver

The liver is central to the keto diet. "When carbs are restricted, the liver shifts gears and converts fat into ketones," explains Dr. Dhruv Kant Mishra, Gastroenterologist. For people with fatty liver disease or prediabetes, this can actually be beneficial—improving insulin sensitivity and reducing liver fat but not everyone wins.

"Without supervision, a high-fat diet can overwork the liver, raise enzyme levels, or cause inflammation," Dr. Mishra cautions. The quality of fats matters, as does duration and individual liver health.

His advice is simple, don’t do keto solo. Especially for those with any liver conditions, professional monitoring is essential.

Kidneys

Keto affects kidney function more than most realize. "Lower insulin leads to sodium loss, which can cause dehydration and mineral imbalances," says Dr. P. N. Gupta, Nephrologist. This is usually manageable with more water and electrolytes—but not always.

High animal protein intake—a hallmark of some keto diets—can increase acid buildup and strain the kidneys. "For people with underlying kidney issues, this can be dangerous. Even healthy individuals may face higher kidney stone risk due to changes in urine pH and calcium levels."

Dr. Gupta also flags the risk of gallstones and nutrient deficiencies with long-term keto. His recommendation? Anyone with kidney, liver, or metabolic conditions should only try keto under medical supervision.

The ketogenic diet can yield real health benefits—but it's not a universal fix. Depending on how it's implemented and who’s following it, keto can either help or harm.

Every expert agrees on this: choose clean, whole-food fats, stay monitored, supplement as needed, and work with a qualified healthcare provider.

Done right, keto might improve your metabolism, heart health, cognitive function, and skin. Done wrong, it could damage vital organs and disrupt body systems in ways that aren’t immediately obvious.

So before you jump in, pause and understand your body, talk to your doctor, and remember—no diet should be a gamble with your long-term health.

Coffee is an essential part of our day, whether we begin our day with it or have it at small intervals other times. However, have you ever wondered how long does it take for coffee to get absorbed into our body? And how long does it take to get absorbed into our bodies?

Caffeine gets into your system quite fast, usually within 45 minutes of drinking it. The highest levels of caffeine are typically seen between 15 minutes and up to two hours later, depending on the individual and if you drink it with food.

For most healthy people, about half of the caffeine you consume is cleared from your body in roughly five hours. This is known as its "half-life."

Many things can affect how quickly your body processes caffeine, including your age, sex, whether you're pregnant, your weight, and if you smoke. Some people are more sensitive to caffeine because of differences in the enzymes in their liver that break it down.

What Happens When You Have Caffeine In Your System?

The Cleveland Clinic explains that caffeine can make you feel more awake, alert, and focused, and it can even improve your mood. However, too much caffeine can cause negative effects like higher blood pressure, an upset stomach, and jitters. In very rare situations, a caffeine overdose can even be life-threatening.

Caffeine's Impact on Your Brain

As a stimulant, caffeine makes your central nervous system more active, which controls everything from thinking to moving. It boosts wakefulness by blocking a brain chemical that causes tiredness, making you feel more alert. It can also improve focus and mood by activating other brain chemicals. However, too much caffeine can lead to anxiety, jitters, and trouble sleeping, as it over-excites your nervous system.

Caffeine and Your Heart

While moderate coffee drinking may benefit heart health by potentially lowering blood pressure and cholesterol, caffeine can also have negative effects. It can cause mild increases in blood pressure and heart rate, which might be problematic for those with existing heart conditions. Higher doses of caffeine can lead to heart palpitations, making your heart feel like it's racing or fluttering, though these are usually not dangerous.

Caffeine and Your Digestive System

Too much caffeine can cause digestive issues. It has a laxative effect by stimulating the gut and speeding up food movement, which can lead to diarrhea in sensitive individuals. Caffeine can also increase stomach acid production and relax a muscle that prevents acid reflux, resulting in uncomfortable heartburn. Coffee's natural acids can intensify these digestive problems.

Caffeine's Effects on Other Body Systems

Caffeine acts as a diuretic, meaning it helps your body eliminate excess fluid, which might lead to more frequent urination. While unlikely to cause dehydration on its own, it's crucial to also drink plenty of water. Furthermore, caffeine can reduce your body's ability to absorb calcium, potentially affecting bone strength, especially with high consumption or insufficient dietary calcium.

How Much Caffeine Is Too Much?

Drinking too much caffeine can cause unwanted effects like feeling anxious, having a fast heartbeat, feeling restless, and having trouble sleeping.

The US Federation and Drug Administration generally recommended that adults keep their caffeine intake under 400 milligrams per day to avoid taking too much. People who are sensitive to caffeine might want to limit themselves to just one or two cups of caffeinated coffee or tea per day to prevent side effects like jitters and sleep problems.

Because caffeine stays in your system for a while, it's a good idea to avoid caffeinated drinks, like coffee, before going to bed.

How Long Before Sleeping Can You Have Caffeine?

A 2013 study published in the Journal of Clinical Sleep Medicine suggested that one should avoid drinking coffee at least 6 hours before sleeping. Researchers found this by giving participants 400 mg of caffeine at 0, 3, or 6 hours before their usual bedtime, comparing it to a placebo.

The findings showed that caffeine significantly disturbed sleep at all three time points, reducing total sleep time. This suggests that even caffeine consumed six hours before bed can negatively impact sleep, supporting the recommendation to avoid significant caffeine use for at least six hours before bedtime.

In a discovery that may make some rethink their morning ritual, new research has found a potential link between drinking instant coffee and a significantly higher risk of developing age-related macular degeneration (AMD), a leading cause of blindness among older adults.

The findings, published in the journal Food Science & Nutrition, are based on data from more than 500,000 individuals in the UK Biobank.

Researchers observed that participants who regularly consumed instant coffee and carried a specific genetic predisposition were up to seven times more likely to develop dry AMD—the more common and currently untreatable form of the disease.

What is Dry AMD?

Dry AMD gradually damages the macula, the central portion of the retina responsible for sharp, detailed vision. Over time, it can lead to blurred sight, difficulty in reading, and eventually, irreversible vision loss. While age and genetics are the most recognized risk factors, researchers have long suspected that lifestyle and dietary choices also play a role in the progression of this disease.

Coffee and Its Complicated Role in Health

Coffee is one of the most consumed beverages globally and is often touted for its health benefits. Rich in antioxidants and polyphenols, it has been associated with a lower risk of conditions like Parkinson’s disease, type 2 diabetes, and even some cancers. However, not all coffee is created equal.

This new study adds a surprising twist—instant coffee may not offer the same protective benefits as brewed coffee and may, in fact, be linked with negative outcomes for eye health, especially in people with certain genetic backgrounds.

Genetic Factors and Coffee Preference

The researchers behind the study believe that the preference for instant coffee might itself be influenced by genetic factors. Their analysis suggests there could be a shared biological mechanism between genes that influence coffee consumption habits and those that increase the risk of AMD.

This doesn’t necessarily mean that instant coffee directly causes AMD. However, the correlation hints at a complex interaction between genetics, dietary choices, and disease risk that warrants further investigation.

Dry AMD is a growing public health concern, especially in industrialized nations where people are living longer. It affects millions of people globally and can severely reduce quality of life. Given its slow but progressive nature, early detection and lifestyle management are key to preserving vision.

The new findings could pave the way for more personalized lifestyle advice based on genetic risk.

For example, individuals identified with a higher genetic susceptibility to AMD might benefit from moderating their intake of instant coffee or switching to brewed varieties.

More Research Is Required

While the study’s findings are compelling, researchers caution that more work is needed to establish a causal link. Future studies are expected to examine whether instant coffee itself contributes to retinal degeneration, or whether other factors—such as additives, processing methods, or associated lifestyle habits—may be at play.

Long-term population studies and deeper exploration into the metabolic pathways involved will be critical to understanding the full picture. Until then, the study offers a timely reminder that even seemingly minor lifestyle choices, like the type of coffee you drink, could have long-term implications for health—especially when genetics are involved.

For now, experts recommend a balanced approach that includes regular eye check-ups, a nutrient-rich diet, and avoiding smoking—alongside being mindful of what’s in your coffee cup.