7 Diet Myths Explained

There’s a reason people make fun of diets – they change so frequently that over time, most of us aren’t even sure if they work. As most would agree, eating less sugar and carbs, and adding more fresh greens in your diet doesn’t hurt. However, some diet myths still persist – here are some of them:The Conversation

1. Green tea speeds up metabolism

Many of you may have heard that drinking green tea will raise your metabolism, and help you burn calories. The caffeine in green tea does raise metabolic rates slightly, but it’s no different an effect from coffee – it works out that 3-5 cups of tea a day helps you burn 70 calories (however, you can do more fun things – from throwing frisbees to skateboarding – to burn that in 20 minutes). Some reviews also noted that regular consumption of green tea didn’t help people keep weight off.

2. Not eating after 7pm speeds up weight loss

You may actually practise this habit, which makes sense. However, it’s not the time of day that matters, it’s what and how much you eat. If you manage to burn off enough calories that you eat after 7pm, then your body won’t store the excess fat. There’s also a recent review that found that it makes no difference to your body weight if you eat one, two or three meals per day. However, some studies found that eating most of your calories late in the day can make your blood sugar control worse, so on the safe side, if you need to eat late, don’t binge on carbohydrates.

3. Drinking water before meals makes you lose more weight

Funny enough, this one may work on some people. According to a trial, an observation on obese adults found that those who drank 500ml of plain water 30 mins before breakfast, lunch and dinner, lost 1.3kg more weight than those who only visualised their stomach being full. However, studies on the effects of drinking more water revealed highly variable results. In any case, drinking plain water is much better than drinking anything sugary, like soft drinks, cordial, or even juice.

4. Ketogenic diets are better than other diets

The popular ketogenic diet is one where you drastically cut carbohydrates, and instead eat foods that are very high in fat and protein. A meta-analysis of 13 weight loss studies found that those on ketogenic diets lost about 900 grams more than those on a low-fat diet. According to analyses, those on ketogenic diets had reduced hunger and a lower desire to eat, while those on low-calorie diets (under 2,500 kilojoules per day) had significantly lower hunger levels, with greater fullness. However, both types of diets are very restrictive and one should consult their doctor before embarking on one due to the potential side effects (ie. headaches, gall bladder disease, etc)

5. Don’t eat before a work-out to burn more fat

Some people are still on the fence on this, but a study revealed that those who fasted before exercise showed 15% more fat burning during exercise, compared to those who ate breakfast. However, eating breakfast led to a 20% greater total exercise energy expenditure.

6. Celery has “negative” calories

Some of you may have heard that eating celery actually helps you burn more calorie than you ingest. Sure, celeries are low in calories (a 15cm stalk has 5 calories), but your body uses only about 10% of the veggie’s total kilojoule value (19) to digest it – so just 1-2 kilojoules. The only real ‘food’ with a ‘negative’ calorie count is cold water because your body needs to warm up the water to body temperature before it’s absorbed – heating uses up kilojoules – so technically get negative calories.

7. Eating grapefruit melts fat

One of the most persistent diets for weight loss is the ‘grapefruit diet’, which perpetuates that the polyphenols in grapefruit (which is also found in my other fruits and veggies) helps break down fat, and the fibre content makes you feel full. However, eating grapefruit in addition to your regular meals won’t give you any effect – but a diet with enough fresh fruits and veggies, and fibre will. Besides, a meta-analysis of three randomised controlled trials on the effect of eating grapefruit on body weight found no change in body weight compared to controls.