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How to lose weight fast

Tamara Willner
Written by

Tamara Willner

Medically reviewed by

Fiona Moncrieff

9 min read
Last updated July 2024

The truth behind fast weight loss is this: it’s tough to lose weight fast, and if we do, then we usually regain it – this yo-yo dieting can last for years.

Many people feel the need to try rapid weight loss to help them achieve a healthy weight. This often leads to restricting calorie intake, taking supplements, and dramatically increasing physical activity.

Diets that promote fast weight loss and reduction in body fat usually promote strict calorie deficits and leave you hungry and deprived.

Because of this, fad low-calorie diets produce short-term results and ultimately fail, as they’re difficult to stick to.

Additionally, much of the weight you lose at the beginning of a weight loss journey is water weight. Both stored carbohydrate (glycogen) and fat are stored with varying levels of water – so that initial drop you often see with fad diets isn’t necessarily the weight you want to lose.

How to lose weight fast: Time to shift your approach

This is why it’s essential to move away from the mindset of losing weight quickly and shift towards a mindset of making healthy lifestyle changes that will support sustainable weight loss.

Rather than aiming to eat fewer calories and develop an unhealthy relationship with food, following a balanced, lower-carb diet based on whole foods is the best way to lose weight fast and keep it off.

It’s important to note that nutrition is only one of the factors affecting weight loss. Exercise, mindset, sleep, and stress are all equally important to effectively make healthy changes.

Following a weight loss plan that includes all the different aspects of health can be the most effective way to begin a weight loss journey.

At Second Nature, we help you move away from the vicious cycle of losing weight and putting it all back on again.

You’re supported by a registered dietitian or nutritionist who provides personalised support to help you on your weight loss journey.

If you want to join over 150,000 people like Jo who’ve successfully lost weight fast and kept it off with Second Nature, the first step is to take our health quiz, which you can click on here.

Otherwise, keep reading as These top weight loss tips will help to kick start your healthy lifestyle changes and ensure the fastest, most effective results.

1) Consider carbohydrates

Carbohydrates are an energy source for our bodies and provide our cells with food (in the form of glucose). Lower-carb diets are a common weight loss tool.

The rationale behind a lower-carb diet based on whole foods is that healthy fats and protein are digested slower than carbs, leaving you feeling fuller for longer.

Including high-fibre carbs like whole grains and veggies also helps keep you feeling full to support weight management.

High protein and healthy fat (such as olive oil and avocado) intake also help keep our blood sugar (glucose) levels stable throughout the day. These factors reduce the likelihood of feeling deprived and snacking.

A balanced intake of all the food groups is the best way to ensure we’re giving our body everything it needs to function well.

Low-carb is also thought to help with weight loss by lowering insulin. Insulin is one of the hormones responsible for regulating blood glucose levels, but it also promotes fat storage in the body.

The more extreme ketogenic (keto) diet eliminates carbohydrates almost entirely and focuses on eating a lot of fats instead. This deprives our body of its primary source of fuel, glucose.

The body then creates new metabolic pathways and starts burning fat (or, more accurately, ketones produced from the breakdown of fats) for energy instead. This process is called ketosis.

While the keto diet burns fat, it’s pretty challenging to follow effectively in the long term, as one slip-up temporarily takes you out of ketosis.

Similarly, highly restrictive popular diets, such as the Atkins or Dukan diets, reduce carb intake but also provide many strict rules, making them tough to follow in the long term.

A lower-carb approach has many other benefits, including lowering the risk of type 2 diabetes and heart disease.

Overall, it seems that a lower-carb diet, but not a carb-free diet, is probably the most effective way to lose weight relatively quickly and keep it off.

A study comparing the weight loss over two years between low-fat, low-carb, and Mediterranean diets demonstrated that the low-carb diet produced the most short-term weight loss.

At the two-year mark, the low-carb group had maintained weight loss significantly more than the low-fat group.

Graph depicting weight loss over 2 years for a low-fat, low-carb and Mediterranean diets.
When you eat carbs, you should opt for complex carbohydrates (for example, sweet potato, oats, quinoa, or wholewheat pasta).

These have a larger molecular structure than simple carbohydrates (for example, white rice, white bread, or white pasta) and contain more fibre. Fibre makes us feel fuller for longer and has many other health benefits.

It’s also recommended to drink water throughout the day to stay hydrated; this will also help to keep the hunger pangs at bay.

Key points:

  • Reducing the number of carbs we eat means we naturally eat more protein and fats, leaving us feeling fuller for longer.
  • Eating a lower-carb diet also lowers insulin, which promotes the storage of fat in our bodies.
  • Whilst the keto diet, which almost entirely eliminates carbs, sounds ideal for weight loss, it can be challenging to follow effectively in the long term, whereas a lower-carb approach is more simple.

2) Limit ultra-processed foods

Ultra-processed foods can be defined as industrial formulations made with five or more ingredients, for example, biscuits, crisps, cakes, and fizzy drinks.

These foods have been manufactured to appeal to our reward systems. They contain the perfect amount of fat and sugar that keeps us returning for more, known as ‘the bliss point’. This is the reason many of us struggle to stop eating junk food.

Our guide on junk food explores the best way to kick these cravings. As well as trying to avoid the obvious ultra-processed foods (e.g. biscuits, chocolate, cakes), it’s worth looking out for less obvious ‘bliss point’ foods (e.g. sauces, dressings, dips, bread).

Suppose we eat balanced meals made up of whole foods rather than consuming a large amount of ultra-processed foods. In that case, we can enjoy them occasionally without guilt or intense cravings.

Key points:

  • Ultra-processed foods can be defined as industrial formulations that have been made with five or more ingredients, for example, biscuits, crisps, cakes, and fizzy drinks.
  • It’s easy to overeat these foods as they are formulated to appeal to our reward systems.

3) Beware of fat-free

A common myth is that fat makes you fat. In line with this myth is that low-fat or fat-free products are crucial to reducing body fat and healthy eating. This isn’t always the case.

Often, manufacturers replace fat with sugar to add flavour, especially in dairy products. That’s why so many seemingly healthy dairy products, particularly flavoured ones, are low-fat or 0% fat.

These products contain much more sugar than the full-fat options, so they’re not necessarily a healthy alternative.

So, it’s important to check food labels in supermarkets. Let’s look at different yoghurt products from the same brand as an example:

Comparison of full-fat natural yoghurt with 0% fat flavoured yoghurt.

By changing from 0% fat-flavoured yoghurt (14% sugar, highlighted in red) to full-fat, natural yoghurt (5.6% sugar, highlighted in green) you can reduce the amount of sugar eaten by almost three times.

Sugar has several harmful effects on our health, from reducing energy levels to increasing sweet cravings.

These can have knock-on effects on preventing you from exercising and driving you to snack on ultra-processed foods more, slowing down any weight loss.

Our guide on reducing sugar intake explores the best practical ways to reduce sugar intake.

On top of this, the fat in full-fat natural yoghurt will help to keep you fuller for longer. As previously mentioned, fats are digested slower than carbs or sugar, keeping you feeling satisfied and reducing the chances of cravings.

Key points:

  • Low fat or fat-free products are not necessarily a healthy alternative.
  • Low-fat flavoured dairy products often contain huge amounts of sugar as a replacement for the fat.
  • Fats will keep you fuller for longer, whereas sugar will increase cravings and cause our energy levels to fluctuate.

4) Exercise

Exercise isn’t just about helping you burn calories; all types of exercise, such as cardio and resistance training (strength training), can significantly benefit our mental health and improve the quality of our sleep.

Research published in the official review journal of the World Obesity Federation suggests that combining dietary changes with exercise provides significantly more weight loss than dietary changes alone.

This research combined trials looking at more prolonged, less intense exercise with trials focusing on shorter, more intense exercise. However, the evidence suggests that shorter, intense bursts of exercise result in more weight loss.

In our guide on finding the time to exercise, we discussed a study that compared high-intensity exercise to more extended steady exercise.

Results demonstrated that those in the high-intensity group lost significantly more fat than those in the steady exercise group.

Infographic explaining a trial that demonstrated that HIIT exercise was the most effective for weight loss and insulin sensitivity.

In this study, their diet was controlled, so the differences in weight were likely down to the differences in exercise.

The researchers suggested that high-intensity exercise positively impacts certain stress hormones released by the kidney that accelerate fat burning.

So, if you are trying to lose weight quickly, consider adding some short, intense bursts of exercise to your daily routine.

High-intensity exercise has also been shown to help us lose belly fat, increase our muscle mass, and stop us from overeating. Exercise seems to support the satiety signals (hunger and fullness) to the brain – helping to stop us from overeating.

Key points:

  • All types of exercise benefit our health, both mental and physical.
  • Shorter bursts of high-intensity exercise seem to be the most effective for fat loss.

5) Sleep

Evidence suggests that poor sleep increases feelings of hunger and food intake. There are also several other reasons why getting enough good quality sleep is important.

If we are feeling low on energy and experiencing strong sweet cravings, we are less likely to exercise and more likely to snack on ultra-processed foods and avoid healthy foods.

This would slow down weight loss, and prolonged poor-quality sleep might lead to weight gain.

Our guide on increasing the quality of our sleep examines the best ways to ensure a good night’s sleep.

Key points:

  • A lack of sleep, or poor quality sleep, can strongly influence our food choices.
  • When we’re tired, we are less likely to exercise and more likely to experience sweet cravings.

6) Stress

Stress can lead to weight gain in several ways.

Stress can impact our food choices, making us favour energy-dense foods. On top of this, research suggests that stress can lead to weight gain independently from our diet by influencing our hormones.

Overall, science suggests that managing our stress levels is equally vital to changing our diet and exercising to achieve our weight loss goals.

Key points:

  • Stress can impact our food choices and our hormones leading to weight gain.
  • It’s important to manage our stress levels, as well as focusing on diet, when we are looking to lose weight.

Take home message

  • Eating a lower-carb diet where you reduce, but don’t eliminate, the number of carbs you eat seems to be the most effective for fast weight loss that can be sustained.
  • Limiting ultra-processed foods and having three balanced meals daily are the best ways to reduce cravings.
  • Fat-free products are not necessarily a healthy alternative to full-fat and leave us less satisfied, as the fats are digested slower than sugar.
  • All types of exercise benefit our health, both mental and physical.
  • Shorter bursts of high-intensity exercise seem to be the most effective for fat loss.
  • Sleep and stress can impact our hormones, food choices, and energy levels, which means they’re both important factors for weight loss.
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