09 Aug Weight loss myths

There are so many weight loss diets around that it can be difficult to know which ones are healthy, effective and safe. We’ve taken three common myths around weight loss and helped to unravel the truth behind them. 

Myth #1: Carbs cause weight gain

The truth

In simple terms, weight loss happens when you eat less calories than you expend each day. Whether the calories come from carbohydrate, fat, protein or alcohol, if you consume more calories than you use, you will gain weight – and vice versa. Having said this, carbohydrates are often the food group limited in weight loss diets because carbs cause fluctuations in blood sugar levels (and therefore energy and hunger levels), and they’re also easy to over-eat. This is because carbohydrates have a low satiety (fullness) rating.  For example, if you eat a tablespoon of sugar vs a tablespoon of fat, you will feel fuller after the fat than the sugar.

But cutting back on carbs particularly for any length of time can be a disaster for weight loss as this may lead to reductions in the appetite hormone Leptin. When levels of Leptin fall too low (often seen in crash dieters), it signals to the brain that more energy is needed so hunger levels increase and more fat is stored in the body. Neither of which is good for weight loss! The key is to choose unrefined carbohydrates like oats, brown rice, wholemeal bread, rye bread and buckwheat as these have more fibre than refined carbs like bagels, white pasta, sweets, cakes and biscuits. This means they will be more filling and have less of a spike on blood sugar levels, whilst helping to keep leptin levels steady.

Myth #2: Low fat dairy is better than full fat

The truth

For years we’ve been told to choose skimmed milk and low-fat dairy products over full-fat, yet the results of Women’s Health Study which looked at dietary habits of over 18,400 women, found that those who consumed high-fat dairy products reduced their risk of being overweight or obese by 8%. One explanation for this is that when people cut out fat, they tend to compensate by increasing sugary or carbohydrate-rich foods, which eaten in excess will lead to weight gain.

Another suggestion is that the fat from the full-fat dairy products may work directly in the body to help break down sugar. In addition to this, calcium (found in all dairy products) may help with weight loss due to its action on fat cells. All of these are great reasons to include full-fat dairy products in a weight loss diet.

Myth #3: Exercise is key for weight loss

The truth

For many people, weight loss is the main reason they hit the treadmill. Yet studies have shown that not only does exercise lead to only a moderate increase in calorie expenditure (a 30 minute jog averaging about 250 calories), but exercise can often lead to ‘over-compensation’ with calorie intake. You may’ve experienced that over-eating after exercising because you feel you’ve either ‘earnt it’, or because you feel hungrier.

In studies which have compared the effectiveness of diet vs exercise on weight loss, most studies show that exercise alone has little if any effect on weight loss, whereas dietary calorie restriction almost always has a positive effect. Despite this, it’s been shown that people with more muscle mass use more calories, so by increasing your muscle mass through regular exercise, particularly through strength training, you’ll be able to slightly increase your daily calorie burn. Don’t put your trainers away though – aside from weight loss, staying physically active has numerous health benefits, including reduced risk of cancer, heart disease, depression and better quality sleep.

Written by Ruth Tongue

(MSc Nutrition)