Trying to lose those last few kilos? We have some tips for you. Photo / Getty Images
If you need to lose weight, but are getting nowhere, it can be very disheartening. Healthy Food Guide examines the latest science to see what might be standing in your way.
Trying to lose a few kilos? You're probably in very good company, given around two-thirds of us are overweight or obese. But losing weight, and keeping it off, is notoriously difficult. And it's not about a failure of willpower.
One of the reasons people struggle with long-term weight loss could be the restrictive diets we embark on to do it. While they might deliver immediate results, they don't work long term because the behaviours they demand aren't sustainable. So, we quit the diet, and regain the weight.
But what if you're having trouble losing even a little, or any, weight, despite trying to eat more healthily and exercise more? Scientists have been seeking answers to that frustrating scenario for decades, and the good news is that they've now uncovered several reasons that might explain why weight won't shift and, more importantly, what you can do about it.
Past research has shown …
People often use eating as a stress-management strategy, and that stress makes high-fat, high-sugar foods, like biscuits and chocolate, seem more appealing. There's a good reason for that. A 2011 study from the University of California found "comfort foods" might change the way our bodies respond to stress by suppressing the release of stress hormone cortisol. As a result, comfort eating can become a way of self-medicating.
But we now know …
Unhealthier food choices could cause a bigger weight gain when we're stressed, compared with eating them in a stress-free state. That's what results from a 2019 Australian study using mice suggest. The researchers found a molecular pathway in the brain, controlled by insulin, that triggers more weight gain in times of stress.
It means we need to …
Be especially mindful about our food choices when we're stressed and be conscious that the unhealthier options will be more tempting.
Instead, try to find a non-food way to dampen cortisol levels. The latest research shows that spending 20 to 30 minutes in a place that makes us feel in contact with nature can lower stress levels.
Past research has shown …
When our diet doesn't contain enough protein, we overeat. In a 2011 study 22 lean people were provided food over three separate four-day periods. It was found that when they ate meals with just 10 per cent energy from protein, they consumed around 1000 kilojoules more a day, just to satisfy their hunger, compared with when they were eating meals with 15 per cent energy from protein.
One explanation is called the protein-leverage hypothesis, which says the body has a fixed protein target. If you replace some all-important protein with fat or carbohydrates, your body will send signals to keep eating until you hit your protein target.
But we now know …
When our goal is weight loss, we need to eat more protein than was previously thought to hit that "enough" target.
The latest science recommends eating at least 1.2g of protein per kilogram of your body weight every day for optimal weight loss, assuming we're reducing total kilojoules. This helps counteract the loss of muscle mass that often occurs with weight loss and helps with satiety.
It means we can …
Work out how much protein is needed each day and aim to include at least 20g-30g protein in each meal to maximise protein's hunger-busting potential. For example, a 70kg woman would aim for around 84g of protein a day, eating protein-rich foods such as:
20 almonds - 5g protein
½ cup plain low-fat yoghurt - 6g protein
1 large egg - 7.5g protein
¼ cup cottage cheese - 9 g protein
½ 400g can chickpeas - 10g protein
95g can tuna - up to 22g protein
120g chicken breast - 26g protein
Past research has shown …
Rather than trying suddenly to implement too many major lifestyle changes, adopting fewer, smaller ones is what works. In fact, a 2012 study found that even small, regular increases in activity, such as 1000-3000 more steps a day, helped people lose weight and keep it off.
But we now know …
Your ultimate success in implementing those small changes depends on how you frame them. A study published in 2018 found that if the changes you want to make contain a combination of "stop doing this" and "start doing that" behaviours, you will find it harder to make any of them stick, compared with when your changes are all "start" or all "stop" ones.
It means we need to …
Choose "stop doing" changes to begin with — which the 2018 study found were the most effective for creating lasting change around diet and exercise-related behaviours. So, rather than "start standing more", try instead to "stop sitting so much".
Past research has shown …
There's a link between body weight and gut health, and people who are genetically predisposed to grow specific types of gut bacteria are more likely to maintain a healthy weight. Research has also shed light on how the presence or absence of certain bacterial genes, as well as particular bacteria, influence how easily you'll lose weight by eating a healthier diet.
But we now know …
Regardless of your genes, there are things you can do to alter the makeup of your gut microbiome. And we know that by doing so, you can significantly improve your weight-loss efforts. That's according to a 2018 US study which pinpointed dietary changes as an effective way to knock your gut bacteria into weight loss-friendly shape.
It means we need to …
Eat plenty of those foods that act either as prebiotics, which nourish your gut's good bacteria, or which deliver a hit of probiotics, the healthy bacteria. Prebiotic-rich foods include veges such as garlic, onion, fennel, sweet corn, legumes and cooked-then-cooled potatoes. Good sources of probiotics include some yoghurts and fermented vegetables such as kimchi and sauerkraut.
Past research has shown …
A lack of sleep makes us hungrier and leads us to eat significantly more food the following day. A small 2012 study found a sleep deprived group, who slept one hour and 20 minutes less than a control group for eight days, consumed, on average, 2300 kilojoules more each day. We also know that even if you avoid eating more when you're tired, lack of sleep affects the quality of your weight loss. A small 2010 study found that while participants following a strict diet might lose the same amount of overall weight, regardless of how well rested they are, sleep deprivation reduced their fat loss by 55 per cent.
But we now know…
In addition to day-to-day tiredness playing a big role in weight loss, sleep consistency does too. Results of a 12-month study released this year show people who slept for the same number of hours every night lost a little more weight than those whose sleep hours varied from night to night, even though they were all eating the same Mediterranean-style diet.
It means we need to …
Aim for roughly the same number of hours sleep each night, rather than thinking we can short-change ourselves one night and catch up the next to avoid sleep deprivation. And the sleep "sweet spot" to aim for when trying to lose weight? The 2019 study says six hours or less a night is too little, while between seven and nine is just right.
So, if dieting isn't the key to long-term weight loss, what is? Recent research suggests the following three strategies.
Write what you bite
Past research has identified keeping a food diary as one of the best predictors of successful weight loss, and a brand-new study confirms it.
It also shows you don't need to spend a lot of time doing it, or worry about recording minute details, either. The most successful participants spent only around 15 minutes a day altogether on the task, down from 23 minutes when they started out. And logging food intake more often, after every meal, rather than trying to record everything you've eaten at the end of the day, was most effective for weight loss.
Start moving more
Results of research into whether exercise alone is enough to produce significant weight loss are mixed. But a study published this year does confirm that even without making any dietary changes, increasing how much physical activity you do is worth it for your waistline. Give it a few weeks and you're likely to start making healthier food choices without struggling, or even really trying to do so.
Don't eat too late
At least two studies published this year confirm that late-night meals contribute to weight gain, even when overall kilojoule intake is within the healthy range. It's probably thanks to the way eating — when you really ought to be heading to bed — desynchronises your body clock and confuses the bodily processes involved in weight loss and gain. Aiming to have dinner earlier is a great way to help shift kilos.
This article first appeared in Healthy Food Guide and is republished here with permission.
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