Almost everyone who struggles with weight has been there: Losing weight is cinch, but the biggest battle is keeping it off.
So why is persistent weight maintenance so difficult?
One of the main explanations you hear around town is a drop in metabolism. "The idea has merit, but it only reveals part of the picture" says nutrition scientist, Dr Tim Crowe.
Our eating habits are very individual and change from day to day, which is why it's much easier to measure changes in metabolism compared to accurately tracking what and how much a person eats, reports News.com.au.
Here are the top four reasons you regain weight and how to prevent it.
You want a quick fix
As a society we've become hard wired to expect everything quickly. We want instant success in everything we do and all our wants and needs to be fulfilled without delay.
Weight loss, though, is anything but immediate. Regardless of whether you continually count calories, avoid carbs or whatever the diet demands, you may get rapid results in the short-term (which is a big motivator for people), but then you need strategies to move into long-term patterns - which is why these regimens don't address the underlying reasons why you are overweight.
The sobering reality is the human body will continue to fight against weight loss long after dieting has stopped.
The fix: A better approach is to take the focus off "the quickest way to lose weight". Instead, look for positive lifestyle changes which allow you to adapt to new healthy habits, making it less likely that you will revert to old ways.
You're ravenous (all the time)
A recent clinical trial tested a new drug for treating diabetes on two groups. Results showed that people on the drug, called canagliflozin (which works by making the kidneys excrete more glucose - a favourable side effect for weight loss), lost only slightly more weight than the non-drug group.
Why? People in the drug treatment group were hungrier which drove them to eat an extra 100 calories each day for every kilogram of weight they lost.
"The influence of hunger on weight regain is three-times stronger than a slowing of metabolism. Add the two together it appears almost inevitable that the lost weight will creep back on again for most people" adds Crowe.
In other words, the more weight you lose, the more you eventually compensate by eating more.
The fix: Hunger is the physiological need for food, which is why it's important to never ignore it.
Work out a balanced eating plan (including the occasional treat) with a satisfying amount of food that works best for you, and don't be afraid to experiment with eating more if your health isn't where you want it to be.
For a lot of people, weight loss is a journey that requires a lot of mental preparation and sacrifice. Once they reach their goal weight, the "diet" is over - a mindset that sets the scene for regain.
This is amplified by the fact that the body recalibrates its metabolism as the weight drops, however the effort required to maintaining new eating habits are often difficult to sustain.
The fix: The diet mentality needs to stop. Change your mindsets from "weight conscious" to "health conscious".
Refrain from labelling things "good" or "bad" and focus on providing your body with sustaining, nourishing food you enjoy.
Rely on willpower
Ever notice when you decide to give up a favourite food, it's the only thing you can think about?
Restrictive thinking, such as that found in many popular diets, will lead the way down Struggle Street and almost guarantee defeat.
For many, "diet" means a set amount of time during which you must exercise superhuman willpower to resist temptation and overwhelming hunger at the end of which you can finally reward yourself with junk food binge.
"Regaining weight has little to do with poor self-control. Our bodies are primed to fight against weight loss.
You can ignore hunger cues for a time, but they will persist for much longer than your willpower," adds Crowe.
The fix: Identify your triggers to overeat: stress, fatigue, boredom, skipping meals - and build "non-food" strategies, such as go for a walk, call a friend, or take a bath instead, rather than relying on willpower.
Kathleen Alleaume is a nutritionist and exercise physiologist and Author of What's Eating You?