8 scientific weight loss tips

There are so many diet plans, pills, supplements and "miracle tricks" out there - all promising to help you shed pounds in a matter of weeks.

But how many of them have been scientifically proven to work?

While many methods appear to offer quick and pain-free results, you may just be losing water weight, which comes back almost instantly. Worse still, many diet fads have unintended health consequences (Read: 10 most dubious and dangerous diets that could kill you ).

For example, the grapefruit diet is a perennial favourite among celebrities and the public alike, but the science behind it is sketchy at best.

Many doctors agree that eating grapefruit instead of proper meals will help you lose weight, but not because of a "miracle enzyme", but simply because you are consuming less calories in total.

The math is simple: If you take in less calories than you burn, you lose weight. Find out more on the science behind weight loss and what works, and what doesn't in this list compiled by AsapSCIENCE:

#1. Exercise

Yes, I can see you are rolling your eyes. While almost everybody knows that the physical activity of exercise burns calories, did you know that the effects don't just last while you are exercising, but long after you've stopped the activity?

During exercise, your body uses up most of the easy-to-burn available carbohydrates and replaces them over the course of the day. If you do not replenish your body's carbohydrate supply, your body will begin to break down your fat stores for basic functions such as walking, talking and even sleeping.

And did you know that if your activity is intensive enough, exercise hikes your metabolism to burn more calories faster hours after an exhausting session?

In a research paper published in the Medicine & Science in Sports & Exercise journal, research subjects who rode a stationary bicycle at high intensity for 45 minutes burned an extra 190 calories over the next 14 hours.

Another study published in Diabetes Care showed that simply taking breaks from sedentary positions can result in smaller waist circumferences. The breaks can be as simple as standing up more frequently from a sitting position.

In addition, exercise can also help reduce your chocolate cravings and ramp up your ability to cope with stress - a major contributor to expanding waistlines.

What's more, exercise builds muscle mass. Because muscle burns more calories than fat, even at rest, a more muscular person will burn more calories than a couch potato.

#2. Don't skip meals

This runs especially true for breakfast.

When you get up in the morning, your metabolic rate is the slowest, due to your body being at rest for a long period of time. "When you don't eat breakfast, you're actually fasting for 15 to 20 hours, so you're not producing the enzymes needed to metabolise fat to lose weight," said Elisabetta Politi, RD, MPH, nutrition manager for the Duke Diet & Fitness Center at Duke University Medical School.

Not eating breakfast puts our body in "starvation mode", where our metabolism slows to conserve energy.

In addition, it encourages us to mindlessly nibble and binge before and during lunch and dinner. Eating regular healthy meals on the other hand helps to keep blood sugar and hormone levels regular.

That said, there is no need to take a huge breakfast, as if you consume more total calories in a day, you will end up gaining weight. Try eating high-fiber foods that are low in energy density. This will fill you up while allowing you to eat less calories.

#3. Add more protein and low-fat dairy to your diet

According to research done in 2007, the consumption of protein releases a chemical called Peptide YY (PYY).

This chemical in turn travels to the brain and suppresses hunger signals. According to AsapSCIENCE, simply adding 10 per cent more protein to your food can keep you full for much longer.

"We've now found that increasing the protein content of the diet augments the body's own PYY, helping to reduce hunger and aid weight loss," said Rachel L. Batterham, MD, of University College London.

Low-fat dairy on the other hand contains calcium. What calcium does is that it favours fat burning rather than fat storage. It has also been hypothised that calcium bind to fats to create a suplex substance that can't be absorbed.

If it sounds similar to the Atkins Diet - a diet that advocates no-carb meals - it's not. Atkin dieters typically end up eating plenty of fat and oil along with meat - which results in more calories consumed.

The key here is to eat low-fat options. Dairy products provide rich amounts of protein and vital nutrients, but are also known to be rich in saturated fat.

Opt for low-fat dairy products, such as skim or low-fat milk, yoghurt, cottage cheese and hard cheeses instead. According to Livestrong.com, one cup of skim milk contains about 9g of protein and only trace amounts of fat.

#4. Drink soups

Many people think that drinking water with a meal fills them up faster, but science has shown that drinking soup might be a better idea.

When you eat a meal with water, you will feel full for a few hours before the hunger kicks in, BBC News reported. However, if you puree it and blend the food with water, you will stay full for much longer.

Why? According to ultrasounds and MRI scans done of people's stomachs, water drunk passes through the stomach and right out of the sphincter valve into your intestines - which does nothing to fill you up.

However, if you blend solid foods with water, the whole mixture remains in the stomach because the sphincter valve closes to allow digestive juices to do their work.

The stretched stomach in turn stops production of a hormone called ghrelin - an appetite stimulant. The longer your stomach remains stretched, the longer you will feel satisfied.

#5. Count your calories

Keeping a journal to lose weight is one of the more well-researched methods of losing weight.

Scientists at the Fred Hutchinson Cancer Research Center in Seattle found that simple changes in behavior can make a difference on the scales.

In the year-long study, women who kept journals lost 2.7kg more than those who didn't.

"Knowing what you are eating and knowing how much you are eating seem to be the key," said researcher Anne McTiernan, director of the Hutchinson Center's Prevention Center.

If you are trying to lose weight, why not start with the low-cost proven effective method of journals? Researchers advise to record everything that goes into your stomach, and to be accurate. This means you must also measure portions and read labels to see what you are eating.

And don't think you can get away with that extra splash of soy sauce. Any toppings or condiments added to food should also be included in the journal. 

#6. Reduce your plate size and change your plate colour

According to a report published on Medical Daily, eating healthy can be as simple as changing the size of your plate.

A study published in Appetite Australia found that dishware size influences the amout of calories avalable to be consumed in a meal. Another study found that people eat more popcorn when placed in an extra-large bucket than a large bucket.

The problem is, people are often not able to tell when they are full and when to stop before they overeat.

According to AsapSCIENCE, our bodies have a hard time turning down food, even when we are full.

A study gave two groups of participants a bowl of soup to eat. Unbeknown to one group, they were given a bottomless bowl of soup that refilled itself. The group with the bottomless bowl ate 73 per cent more than those with normal 22-ounce bowls, Medical Daily reported.

When the experiment was over, the participants did not realise they had eaten more. 

"Lesson is, don't rely on your stomach to tell you when you're full. It can lie," said Researcher Brian Wansink Ph.D..

And if you want to go the extra mile, why not change your plate to one of a brighter, bolder colour?

A study found that people take more generous helpings when meals are placed on the same colour plate as the food. According to the Cornell University study, when the foods blend in with their background, people tend to serve themselves 20 per cent more than if they were using a plate of contrasting colour.

It is speculated that the colour contrast serves as a "stop sign", signalling to people how much food they are serving. Alternatively, if you want to trick your mind into eating more vegetables, you may want to consider using a green plate.

#7 Relax and get enough rest

Besides being linked to a number of health problems such as heart disease, high blood pressure and cancer, science has also identified links between stress and weight gain.

When your body is put under extreme stress, it releases adrenalin and cortisol to help prepare you for a "fight or flight" response, says well-being consultant and nutritional therapist Laura Holland.

Cortisol stimulates insulin release and maintenance of blood sugar release, which can result in an increase in appetite.

The disruption of cortisol may not only promote weight gain, but also direct weight gain to your abdominal area rather than the hips.

According to a Swedish study, too little sleep also affects the production of cortisol and disturbs other systems in the body, leading to increased fat storage in the abdomen.

A Columbia University study found that people who slept five hours a night were 50 per cent more likely to be obese than normal sleepers.

Besides turning your body hormone levels upside down, it is hypothesised that less sleeping time also means more time awake to head to the fridge for that midnight snack.

#8. Chew longer and eat slowly

A study has found that people who chew their food more take in fewer calories, which may help them control their weight.

Chewing food 40 times instead of a typical 15 times caused study participants to eat nearly 12 per cent fewer calories, according to results published in the American Journal of Clinical Nutrition.

It is believed that chewing for longer gives your brain more time to receive signals from the stomach that it is full, leading to less over-eating.

"Research indicates eating quickly, gorging and binge eating have a substantial effect on being overweight," said the researchers from Harbin Medical University in China.

Still fighting to curb those food cravings? Flip through the gallery below on more tips to fight that uncooperative stomach: