Dr Nick Fuller
Leading Obesity Expert at the University of Sydney and founder of Interval Weight Loss.
Ever felt your jeans getting snug and thought, ‘Is this bloating or actual weight gain?’ It’s a common question—both can leave you feeling off, but they come from totally different causes. Bloating often pops up due to digestive issues or temporary fluid retention, while weight gain is more about your lifestyle and what’s on your plate.
Figuring out the difference can make a big difference for your health. Let’s break down what triggers bloating, how to ease it, and how to tell if it’s bloating or weight gain.
Bloating is that uncomfortable, stretched feeling in your abdomen, often paired with pressure or a visible swelling. It’s common and usually harmless, but understanding the root cause of your bloating is key to managing it effectively. Here are the most common culprits:
What you eat—and how you eat it—plays a significant role in bloating. Gas-producing foods like beans, lentils, broccoli, onions, and cabbage are infamous for causing bloating because they’re high in complex carbs or fibres that ferment in your gut. Fizzy drinks, while refreshing, fill your stomach with carbon dioxide, which can add to the pressure. Eating too quickly or overeating can worsen the problem by trapping air in your digestive system.
Fun fact: research shows that slowing down while eating not only reduces bloating but also helps you feel fuller, which might prevent overeating altogether.
If bloating feels like a frequent guest, a digestive disorder might be the underlying cause. Irritable bowel syndrome (IBS), lactose intolerance, and celiac disease are prime suspects.
IBS affects 11% of the world population, causing a range of symptoms, including bloating. Meanwhile, lactose intolerance means your body struggles to break down milk sugars, and celiac disease triggers an immune response to gluten, both resulting in excessive gas or discomfort.
Feeling bloated after chewing gum or sipping through a straw? These habits may seem harmless, but they often cause you to swallow air. Talking while eating or sipping carbonated drinks while dining can do the same. This swallowed air builds up in your digestive system, leading to that dreaded ballooned feeling.
Sometimes bloating has less to do with gas and more to do with water. High-sodium diets are a big contributor, as salt encourages your body to hold onto fluid. Hormonal changes, especially around menstruation, can also cause fluid retention, adding to the sense of puffiness and discomfort. Reducing your salt intake and staying hydrated can help counteract this effect.
Hormones, particularly during the menstrual cycle, can wreak havoc on your gut. Oestrogen and progesterone fluctuations can slow digestion or cause water retention, leading to bloating. Studies show that people who menstruate may experience bloating as a physical symptom of PMS.
Chronic stress is no friend to your gut. It disrupts the gut-brain connection, slows digestion, and increases the likelihood of bloating. Stress also alters the balance of gut bacteria, which can lead to increased gas production. One study revealed that stress management techniques, such as mindfulness, reduced bloating symptoms in IBS patients.
Certain medications can unintentionally mess with your digestion. Anti-inflammatory drugs, antidepressants, and even some over-the-counter pain relievers can disrupt gut function or cause your body to retain water. If you notice bloating after starting a new medication, it’s worth discussing alternatives with your doctor.
If bloating is getting in your way, try these remedies:
Adjust Your Diet: Limit gas-producing foods and avoid overeating. Opt for smaller, balanced meals throughout the day.
Stay Hydrated: Drinking water helps your body flush out excess sodium and reduces water retention.
Probiotics: Incorporate foods like yogurt, kefir, or probiotic supplements to support healthy gut bacteria.
Regular Exercise: Moving your body, even a short walk, can help stimulate digestion and ease bloating.
Mindful Eating: Slow down and chew your food thoroughly to avoid swallowing air.
Reduce Salt Intake: Cutting back on salty foods can prevent water retention and abdominal swelling.
Herbal Remedies: Peppermint tea, ginger, or fennel seeds are natural remedies that can ease digestive discomfort.
Consult a Doctor: If bloating persists or worsens, seek medical advice to rule out underlying health issues.
Unlike bloating, weight gain tends to happen over time. It reflects more lasting changes in your body’s energy balance, hormones, and lifestyle. Here’s a closer look at the most common causes:
At its core, weight gain occurs when you consume more calories than your body needs. A sustained caloric surplus, even as small as 100 extra calories a day, can lead to noticeable weight gain over time.
For context, 100 calories is about the equivalent of a small banana or a few squares of chocolate. Research shows that high-calorie, nutrient-poor foods are more readily available and often marketed as ‘convenient’, which makes overconsumption all too easy.
When you don’t move enough, your body doesn’t burn the calories it takes in, leading to excess energy being stored as fat. Regular physical activity can help burn calories and regulate hormones and metabolism, reducing the likelihood of weight gain.
Certain hormonal conditions can make it harder to maintain a healthy weight. Hypothyroidism, where the thyroid produces insufficient hormones, can slow metabolism and cause weight gain. Polycystic ovary syndrome (PCOS) affects 1 in 10 women of reproductive age, often leading to insulin resistance and weight gain, particularly around the abdomen. Similarly, menopause can trigger metabolic shifts due to declining oestrogen levels.
Sleep is crucial for regulating appetite and metabolism. Inadequate sleep disrupts two key hormones: ghrelin, which increases hunger, and leptin, which signals fullness. This imbalance often leads to overeating and weight gain. Studies show that people who sleep fewer than 6 hours per night are at a significantly higher risk of obesity compared to those who get 7–8 hours.
Chronic stress doesn’t just impact your mood; it also affects your waistline. Stress triggers the release of cortisol, a hormone that increases appetite and encourages fat storage, particularly around the midsection. Stress eating is also a common response, with cravings for high-calorie, sugary, or fatty foods providing a temporary sense of relief. Over time, this can lead to weight gain if the stress isn’t managed effectively.
It can be tricky to figure out whether you’re dealing with bloating or gradual weight gain, but a few key differences can help you identify the cause:
Bloating is short-lived, usually lasting anywhere from a few hours to a couple of days. In contrast, weight gain happens gradually over weeks or months and doesn’t resolve on its own.
Bloating tends to appear suddenly, often after eating certain foods, during stress, or around your menstrual cycle. Weight gain, however, develops more slowly as a result of long-term changes in diet, activity levels, or hormonal shifts.
With bloating, the swelling is concentrated in your abdomen, making your stomach feel tight or distended. Weight gain, on the other hand, is more evenly distributed across the body, though certain areas like the hips or midsection might show it first.
Bloating often comes with added discomfort, such as gas, cramps, or a heavy, tight feeling in your stomach. Weight gain doesn’t typically cause these sensations unless it’s linked to an underlying health condition.
Bloating might make your clothes feel snug for a day or two, especially around the waist. Persistent tightness in your wardrobe is more likely a sign of gradual weight gain.
A bloated stomach can appear rounded or even protrude noticeably, but the swelling is temporary and related to trapped gas or fluid. Weight gain, on the other hand, increases overall body size without causing this kind of distinct abdominal swelling.
Bloating tends to fluctuate throughout the day—your stomach might feel fine in the morning but distended by evening. Weight gain, however, is consistent and doesn’t fluctuate dramatically from one day to the next.
Recognising the difference between bloating and weight gain can help you take the right steps for your health. While bloating is often temporary and linked to digestion, weight gain usually results from long-term lifestyle factors. Addressing the root causes of either can lead to better overall well-being.
Dr Nick Fuller is the founder of Interval Weight Loss and is a leading obesity expert at the University of Sydney with a Ph.D. in Obesity Treatment. Dr Fuller is also the author of three best-selling books and his work been published in top ranked journals in the medical field, including JAMA, Lancet and American Journal of Clinical Nutrition.