Can you lose weight simply by skipping breakfast, and does your metabolism slow with age? We asked the experts.
Metabolism is the term used to describe the chemical processes that happen in the body. The most well-known of these is turning food into energy.
Our bodies need this energy to do everything from moving and thinking to flushing out toxins and building muscle.
Energy comes from the nutrients in the food we eat and that’s why people can sometimes become hung up on calories as the more energy we use, the more calories we burn and thus lose more weight.
According to Dr Michael D. Jensen from the Division of Endocrinology at the Mayo Clinic in Minnesota, when we perform aerobic exercise, such as running, HIIT or intense cycling, the chemical reactions associated with using our muscles accounts for over 90 per cent of the calories you’re burning. This is why exercise is such a good way to boost your metabolism.
However you’d be forgiven for thinking that using your muscles was the only way we use that energy. ‘The heart and brain are not that big when thinking about the body as a whole, but they each represent about ten per cent of your resting energy expenditure,’ explains Dr Jensen.
‘So, between those two organs that’s 20 per cent of the calories you burn at rest. The liver and other tissues in the abdominal cavity account for almost a quarter of all the calories you burn, and the kidneys require a lot of chemicals to clear products from the blood stream, so that’s another ten per cent of the calories you burn when you’re resting. And, all of the skeletal muscle in the body, even when you’re not doing anything, accounts for 25 per cent of the calories we burn.’
Basal Metabolic Rate (BMR) describes the number of calories someone is burning at rest. ‘This is when they first wake up and are laying still not having eaten anything,’ explains Dr Jensen.
‘Someone doing a resistance training programme, where they gain muscle and lose fat, will burn more calories at rest than they did before they gained the extra muscle because, even at rest, muscle burns calories.
However, it’s not as much as you might think. It’s probably just 10-15 calories a day for each extra kg of muscle so it’s actually very hard to make big changes in your BMR.
‘Despite this, staying physically active and including some form of resistance training in your everyday life is the best way to maintain a healthy metabolic system.’
Myth: Eating breakfast kickstarts your metabolism
‘Eating breakfast isn’t for everyone,’ says Ulrike Kuehl, a dietician with Lumen, who produce the hand-held device that measures metabolism through the breath. ‘It’s better not to force the implementation of that meal.
‘Listen to your body’s hunger cues.
‘Skipping breakfast essentially gives your body more time to process the food or carbs that you consumed the day or evening before. This supports weight loss since your body is more likely to burn fat for energy in the morning.
‘However, breakfast can help mitigate cravings and healthier eating through the day, it simply depends on your routine and cues.’
Myth: Eating smaller, more frequent meals increases your metabolic rate
‘This depends on how much and what you eat,’ says Ulrike. ‘Even if you follow a low-carb diet, eating frequently means your insulin and blood sugar levels increase, therefore making it harder to lose or maintain weight loss.
‘Also, in the long run, eating all the time could impact your body composition thus decreasing your metabolic rate.’
Myth: Eating certain foods can increase your metabolism
‘Everybody is different, therefore would react differently to each food,’ says Ulrike.
‘Contrary to belief there aren’t any “superfoods” that positively affect your metabolism in any significant way. Some studies have shown consuming beverages such as coffee or green tea can temporarily increase your metabolism.
However, studies are inconclusive as to how long this effect will last, and if it affects all individuals. Generally, a fast metabolism is associated with a high basal metabolic rate (BMR), which is a high energy expenditure at rest.’
Myth: It doesn’t matter when you eat
‘Timing is a crucial part of how we eat, in addition to paying attention to what we eat,’ says Ulrike. ‘It’s always best to eat according to your body’s circadian rhythm.
‘Eating at night or at odd hours can slow your metabolism because your body is still utilising the energy (the food) you ate and this can decrease the quality of sleep and the time it takes you to fall asleep.
‘As a result, eating at night means your body has less time to reach a state of burning fat since it is still busy burning food.’
Myth: You can’t change your metabolism
‘While genetics do play a role in the health of your metabolism, it is only one factor out of many that impacts your health,’ says NHS Doctor Emeka Okorocha. ‘Lifestyle factors such as exercise, sleep, stress and, of course, what you eat are equally important.
‘This is quite comforting since anyone can make changes at any time to improve their metabolism just by paying attention to their lifestyle and nutrition.’
Myth: Your metabolism falls off a cliff as you age
‘Your basal metabolic rate does decrease with age but not as quickly or significantly as we’re actually led to believe,’ says Emeka. ‘It’s always possible to improve our lean body mass, which can positively affect our metabolism with an active lifestyle and healthy nutrition.
‘Food is the key to maintaining your metabolism.’Credit: Source