‘What should I eat to lose weight?’ is possibly our most frequently asked question ever. The answer is simple, but often complicated by things like personal preference and dietary requirements, and people’s perceptions of what healthy eating looks like more generally.
Headlines don’t help – a tendency to sensationalise nutritional research in the news means we’re bombarded with seemingly conflicting advice.
Do carbs make you gain weight? Is saturated fat bad for you? Oh wait, is it actually good? What about eggs? And should you eat any of these foods if you want to lose weight? Well.
Let’s look at the evidence for different diets (and by diets here we simply mean ‘what you choose to eat on a regular basis’, rather than a restrictive regimen!).
While this is in line with the old adage of ‘eat less, move more’, and this is generally true, it doesn’t have to mean a calorie-controlled diet.
The best diet for losing weight is the one that enables you to consume less than you use up. Which diet that is entirely depends on you and your personal preference.
The important thing is finding the way of eating that suits you best and that you are able to stick to in the long term.
So many of our users tell us they’ve ‘failed’ at dieting before, that they didn’t have enough willpower. We really believe that you don’t fail the diet, the diet fails you. If you can’t stick to it, then it’s probably not the right one for your needs.
You might have heard that not all calories are created equal – but ultimately total calorie intake has more of an impact on weight than different macronutrient ratios (ie. where you’re getting those calories from).
Various studies comparing diets with different ratios of carbohydrates, fats and proteins showed that the total amount of calories was what determined weight loss.
Patients in a metabolic ward (so a controlled environment, with no opportunities to ‘slip up’ on the diet) were given either a low-carb or a high-carb diet over 6 weeks, and lost similar amounts of weight (and inches).
The evidence is the similar for people living with insulin resistance or type 2 diabetes. Weight loss is still about eating less calories rather than the ratios of protein, fat, and carbohydrates people are having, though different macronutrient ratios may have other advantages.
Some evidence showed that women lost more fat, especially belly fat, on a high protein diet compared to a low protein diet, while another study concluded higher protein meant women lost less muscle when losing weight.
The lower carb diet in the 6-week study did appear to have a greater impact on blood sugar levels than a higher carb diet, which may make it a better option for someone at risk of type 2 diabetes. But for weight loss alone, it was the overall energy intake that mattered, and in any case, weight loss is associated with better glycaemic control regardless.
Using up more energy than you’re taking in – whether through diet, exercise, or both – is key to losing weight. But as we’ve noted above, there are many different ways to do it!
Calorie counting is one way of estimating how much you’re taking in compared to how much you’re using up. But counting calories is by no means the only way to reduce your overall calorie intake, and for some people obsessing over the numbers can actually be counter-productive.
This is usually (but not always) by reducing your intake of carbohydrates, explicitly or otherwise.
Take the Atkins or the Dukan diets, for example, which are high-fat and high-protein, but low-carb. We digest both fats and proteins more slowly than carbohydrates, which generally makes us feel fuller for longer.
Carbohydrates are swapped in for less calorie-dense foods (a lot of vegetables, for example), which tend to have more fibre and water. The same can be said of something like the Paleo diet, to name another.
People tend to shed what is known as ‘water weight’ when they eat less carbs. As your body uses up its glycogen stores, it releases water particles bound up in the glycogen, and you will appear to be losing significant amounts of weight very quickly.
This is what’s usually happening when people go on a crash diet – and is also partly why the weight is so easy to put back on. It’s mostly just water! It is not the same as fat loss.
A study comparing a low-carb and a low-fat diet showed that people on the low-carb diet had lost more weight at 6 months, but that the difference had evened out by 12 months.
A more extreme diet like the ketogenic diet – which eliminates carbohydrates almost entirely, and focuses on eating a lot of fats instead – deprives the body of its primary source of fuel, glucose.
In order to survive, the body then creates new metabolic pathways and starts burning up fat (or more accurately, ketones produced from the breakdown of fats) for energy instead. This is called ketosis.
This may sound ideal, but while a ketogenic diet does burn fat, it is very difficult to follow effectively in the long term, as one slip up will take you out of ketosis.
Neither intermittent fasting nor the 5:2 diet (or any other fasting-based diet) limit your carbohydrate intake, but on a very simple level, they do reduce the time you could spend eating, resulting in less calories in for a lot of people.
This is the same logic behind advice like ‘don’t eat after 6pm’. It’s not the eating late per se that’s impacting your weight, it’s the overall intake of energy that may be more than you need. We as people just happen to be very fond of rules that help us structure our life and help us to lose weight.
Having said that, evidence on intermittent fasting is mixed. This may be because some people tend to compensate elsewhere for skipped meals, for example. As with all the other diets mentioned, it’s about whether that way of eating suits you.
The problem with any of these diets is maintenance. For many of us, they may prove too restrictive, and ultimately unsustainable in the long term.
Evidence shows that most people put the weight back on and more on top when they ‘fall off the wagon’. This can create a cycle of bingeing and restriction, which may lead to yo-yo dieting and weight gain.
Maybe you’re the sort of person who can happily count calories and stick to a certain amount without too much trouble (physical or psychological).
You may prefer not to count calories, and opt for a diet that lets you eat as much as you like of certain foods because then you don’t have the mental barrier of restriction, and your body will self-regulate when you eat enough fats or protein.
You might be perfectly happy to never eat carbohydrates again, like others may want to follow a vegetarian or a vegan diet.
The important thing is to find a way of eating that means you are using up more energy that you are taking in without compromising your health, your energy or your happiness. Only you can work out what works best for you!
Avoid ultra-processed foods and cut down on added sugars. Build your meals around proteins, healthy fats and non-starchy vegetables rather than refined carbohydrates. Fruits, vegetables, beans, seeds, and whole grains are your friends. Move your body as much as possible. If you’re using up more energy than you’re taking in, you will most likely lose weight.
Need some help? We think of OurPath as a process of exploration – we want to help you find the way of eating that suits you best. We give you broad nutritional guidelines you can follow, but also adapt to suit your needs, your preferences, and your lifestyle.
Your mentor is there to help you adapt the nutritional advice so that it fits around your life as it actually is – whether that involves cooking for a family, travelling a lot for work, not being able to exercise or any other barrier that’s making it hard for you to build healthier habits that stick.
Find out more about the OurPath programme.