Healthy eating is one of the best things you can do to prevent and control health problems such as heart disease, high blood pressure, type 2 diabetes, and some types of cancer.

But, the most important part of healthy eating is cutting back on sugar. Overall, the evidence that high sugar drinks promote weight gain is consistent and moderately strong. Sugar has been labelled as "deadly," "addictive,” and "toxic" and it is blamed for the rise in global obesity. Excessive unhealthy food and sugar-sweetened soft drink consumption has been linked to weight gain, as it provides a major and unnecessary source of calories with little or no nutritional value.

So, the key is to get rid of the white sweetness in your diet and you'll free up your body to drop excess pounds.

One study, which focused on the prevalence of weight gain in children who consume sugar-sweetened soft drinks, has shown that a high consumption of high sugar soft drinks predicts increased weight gain.

Another study, published on BMJ.com, proves that sugar intake can have a significant effect on weight over time. The study found that people who ate less sugar lost an average of nearly 2 pounds over a period of 10 weeks while people who increased their sugar intake gained nearly 2 pounds in the same amount of time. These seem like small changes but over time this weight gain can really add up. Over the course of only two years, that’s a 20 pound increase in weight.

Here are the three reasons why quitting sugar helps you lose weight.

1. Cutting out sugar removes a lot of calories

A level teaspoon of white sugar has 16 calories but that's not the problem. It's not just the sugar. It's the company sugar keeps.

If you eliminate sugar-laden foods, you eliminate a lot of calories from fat and refined starches, too. That's because we don't eat sugar on its own. We consume it with fat and refined starches.

Take a look at what you'll save if you say "No" to soft drinks, energy drinks, chocolate biscuits, doughnuts and muffins. For instance, cut out just one can of fizzy drink and you cut out 130 calories and 34g sugar.

Removing soft drink is a strategy often suggested to curb childhood obesity. Even reducing the volume of soft drink – as New York city has proposed with its ban on supersized cups and limiting a single serve to 500ml – can help.

2. Sugar is a "marker" for highly-processed foods

When you quit sugar you're cutting out foods nutritionists have always said you shouldn't eat.

No chocolate, cupcakes, fizzy drinks, caramel frappuccinos or ice cream means you're removing "junk food" that is calorie-dense, of poor nutritional value, that comes in huge portions, and is highly refined with added colours, flavours and preservatives.

What's more, it's usually low in fibre and has a high GI (Glycemic Index). None of these foods is any loss in a healthy diet. You're better off without them.

3. Quitting sugar means more natural, unprocessed foods

What do you replace sugary foods with? Usually it's more fruit, nuts, salads, water or you just eat more chicken, fish meat and vegetables at your meals.

Here are 9 simple swaps to limit your intake of sugar junk foods.

Related article: The Simple Math Behind Weight Loss

Conclusion

You don't have to quit sugar entirely to improve your health and your weight (as the anti-sugar campaigners insist). Moderation, as always, is the key to eating healthily, sensibly and in a way that is easy to maintain. However, if you seriously want to lose weight, eating less sugary junk food is a good thing to do.

Tip: write out your day's intake of food. Circle the sweet foods and drinks you like to consume regularly or in large amounts. The most likely culprits are soft drinks, juices, chocolate, muffins and candy. Or circle the sweet foods you reach for when you need a comfort fix. Cut these out of your diet today.