Doctor explains cause of your 3pm slump — and how to boost energy levels

Brits say they feel the afternoon dip around three times a week with fatigue, low mood and irritability among the most common symptoms. For many, it also means a drop in productivity, snapping at loved ones and reaching for junk food. Yet only 15% make the link between how they feel and what they eat. Dr Rangan Chatterjee said the mid-afternoon slump is one of five key signs your glucose levels may be out of balance. A poll found 55% experience feeling 'hangry' at least once a week but half have never considered glucose as a factor, instead blaming stress or poor sleep. The bestselling author and host of the Feel Better, Live More podcast said lunches lacking protein or fibre can make the dip worse. People then often reach for a quick sugar hit - which can restart the cycle. To help avoid it, he suggests adding a substantial serving of protein to lunch to keep you going beyond slump hour, then going for a brisk 10 to 20-minute walk after eating to help regulate glucose levels naturally. Dr Chatterjee who has partnered with Abbott's Lingo, a biosensor and app designed to help people understand their glucose levels said: "We've normalised feeling exhausted, unfocused and irritable, but these can be early signs that the body is struggling metabolically, and that matters. "Glucose is one of the most important signals in the body, shaping how we feel day to day, from our energy and mood to our focus and sleep, while also playing a role in long‐term health. "Prediabetes is far more common than most people realise and often develops silently. With 6.3 million people in the UK now living with it, many without knowing, there has never been a more important time to listen to what your body is telling you." He added that dips during the day can slow brain signalling, leaving you mentally sluggish and unfocused. Repeatedly rereading the same email without taking it in could be a sign to skip another caffeine hit, drink a glass of water and eat a small handful of nuts, he said. The healthy fats provide a slower-release fuel source that can help stabilise energy. Dr Amy McKenzie, director of medical affairs for Abbott's Lingo, added: "We track our steps, sleep, weight and heart rate, so why not glucose? "It's one of the most important indicators of how your body responds to food, stress and movement, yet for most people it's completely invisible. "Making glucose visible in real time, continuous glucose monitors can turn an unseen signal into something practical and empowering – helping people understand what's really driving their energy, mood and focus, so it becomes something they can act on." Your brain is the most energy hungry organ in your body, and glucose is its primary energy source. When glucose levels dip, the chemical messengers (neurotransmitters) that carry information between your brain cells stop working properly, leaving you with ‘brain fog,’ poor focus, and low mental energy. We experience a natural dip in alertness mid-afternoon as part of our circadian rhythm. However, a glucose crash can exacerbate this and prompt us to reach for quick energy or sugar, which restarts the cycle. If you feel excessively tired or need a double espresso to get through the afternoon, that’s a classic sign of your body crashing after a spike. When your glucose drops, your survival instinct tends to kick in with your brain perceiving a threat and naturally releasing adrenaline and cortisol. If you find yourself snapping at your partner or colleagues when you’re hungry, that’s not necessarily a personality flaw – it could indicate a metabolic cry for help. Your body needs steady energy even while you rest. When glucose levels drop too low overnight, your system releases a surge of stress hormones (like cortisol and adrenaline) to compensate, jolting you awake and disrupting your natural sleep cycle. When glucose levels drop sharply, your body sends urgent signals to replenish energy fast, which often jumpstarts cravings for sugary, high-carb foods. If you find yourself consistently reaching for the biscuit tin, it may be a sign of glucose imbalance. The irony is that giving in to the craving often triggers another spike and dip, keeping you stuck in the cycle.