Marmite (yeast extract) is a rich source of the B vitamins that are required to release energy from food. It's also high in salt, and this is why you must limit its consumption.. You can also get B vitamins from meat, fish, eggs, whole grains, beans and lentils.
Avocado: Fat is more calorie-dense than either carbohydrates or protein, which makes it the strongest energy source. The flip side is that too much fat can make you pile on the flab, and eating the wrong kinds of fat (saturated and trans fats) furs up your arteries. Avocados are rich in heart-healthy, artery-smoothing unsaturated fats, giving you the best of both worlds - energy, plus less risk of a heart attack.
Bananas are power snacks for many of us. Pre-wrapped by the nature and ready to unzip, they're packed with natural sugars and starches, providing a combination of instant and slow release energy. They're also a great source of potassium, which helps keep your blood pressure in check.
Kidney Beans: Like nuts, beans such as kidney beans contain that winning mixture of protein and carbohydrates that keeps you fuelled for longer. But pulses (beans and lentils) are higher in fiber, which slows down the release of energy even more, making beans a true ‘slow-burn' fuel. Cook up some lean mince with a tin of kidney beans, a tin of tomatoes, some chopped onion and as much chilli as possible, for a no-fuss chilli that will keep you going for hours
Coffee: Unlike the foods above, this isn't great nutritional advice - but it works. Caffeine aims the release of adrenaline. It revs you up, gives you a boost of energy, and makes you temporarily more alert. A strong coffee could be just what you need before an significant presentation. But be warned - the energy effect won't last, and when it wears off you'll probably feel more tired than ever.