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What Is Rapid Weight Loss?

Every Question You've Ever Had About Rapid Weight Loss Answered By An Expert

Photographer: Matthew Kelly● Image w/ model: 2 Year Standard Contract. ● Expires: 2/28/2022Restrictions: Editorial and internal use only. No print or advertising.Model: Lynn Kim Do

For years, the idea of rapid weight loss has been deemed dangerous and unhealthy. However, recent studies have shown that rapid weight loss, when done in a healthy and controlled way, might actually be the most effective approach when it comes to achieving substantial and sustained weight loss.

To explain the theory and research further, POPSUGAR Australia spoke to diabetes expert, clinical dietitian, exercise physiologist and CEO and Founder of Be Fit Food, Kate Save, who unpacks this new research and answers all our questions rapid weight loss.

POPSUGAR Australia: What is rapid weight loss?

Kate: Rapid weight loss looks different for every individual as results can vary depending on age, gender, starting weight and lifestyle factors, such as activity levels. The range for rapid weight loss is generally between 3-7kg in the first two weeks, 7-10kg in the first four weeks and 10-15kg in the first eight weeks.

PS: For years, the idea of rapid-weight loss has been misunderstood and deemed dangerous and unhealthy. Can you please unpack this new research, and explain why rapid weight loss may be a more achievable and maintainable form of losing weight?

Kate: When undertaken in a nutritionally sound way, rapid weight loss is not dangerous or unhealthy. On the contrary, a very-low-calorie ketogenic diet that brings rapid weight loss has lots of other health benefits — it triggers a range of favourable metabolic changes including a reduction in blood sugar levels, blood pressure, fatty liver and blood lipid levels (blood fats known as triglycerides). It also reduces our insulin levels in the blood which trigger fat storage and can lead to improved insulin sensitivity over time hence improved fat-burning capacity.

While historically research has indicated gradual or slow continuous weight loss to be the best form of weight loss for long-term success, current research into rates of weight loss is indicating that rapid weight loss is actually the most effective approach and an individual is more likely to achieve substantial and sustained weight loss if the initial weight loss is rapid.

To unpack this a little, individuals who lose rapid weight over four weeks are more likely to achieve and maintain greater weight loss reductions at six months and 18 months in comparison to those who experience gradual weight loss. We have seen this in our Be Fit Food 28 Day Challenge participants time and time again.

Studies have also shown that the amount of weight loss experienced in the initial weight loss phase is significantly associated with the percentage of weight loss maintained. Rapid weight loss results in a higher percentage of weight loss maintained at 12 months, two years and three years.

PS: Is it true that you're more likely to put the weight back on after rapidly losing it?

Kate: A common misconception is that rapid weight loss causes weight to regain plus more. New evidence demonstrates there is no difference between slow and rapid initial weight loss regarding weight regain. Individuals that experienced greater initial weight loss did not experience a greater weight regain than those who lost weight at a slower initial rate.

Rapid weight loss has also been shown to be significantly more likely to achieve a successful and beneficial weight loss maintenance of 10 percent bodyweight reduction at 18 months compared to slow weight loss. Studies have concluded that the greater the initial weight loss in obese patients, the larger the total weight loss at long-term follow up.

PS: What are the different effects of rapid weight-loss and slow-continuous weight-loss on the body?

Kate: A loss of as little as 5 percent of your total body weight, i.e. 3.5kg for a 70kg female, will significantly reduce your risk of having a heart attack or stroke, plus it may also lower your risk of getting two of the most common kinds of cancer (breast and bowel). This is because rapid weight loss lowers inflammatory chemicals and hormones in the body which are linked to being overweight or obese, which in turn are attributed to boosting cancer rates in developed countries.

There are also many studies now showing that rapid weight loss is more effective for Diabetes management and even putting Type 2 Diabetes into remission than traditional low-fat diets. Be Fit Food's study found that just one week on a rapid diet resulted in lower blood glucose levels than the daily average. But the real magic of very-low-calorie dieting though is in the way your body and mind feels even after just one week – you start sleeping better, your energy levels are better and your self-esteem is boosted as your clothes start to feel looser. The natural ketones produced with mild nutritional ketosis even assist with suppressing your appetite at a brain level so that the diet starts to feel much easier.

PS: What are the risks associated with losing weight so quickly?

Kate: There are no evident risks associated with rapid weight loss outside of specific medical concerns and medication implications. In fact, a 5-10 percent decrease in body weight can bring about health benefits including blood glucose control, lowered cholesterol, improved mobility and sleep quality. It may also reduce the need for certain medications.

If there is a history of complex health conditions though, it is important to seek a health professional's advice before embarking on any weight loss program.

PS: Are there any red flags we should look out for?

Kate: Some individuals should avoid a very low-calorie diet, or at least consult a health professional before undertaking this kind of weight loss program, including:

  • Those who have a significant underlying medical condition or require medications
  • Pregnant and breastfeeding women
  • Children under 18 years
  • Those who are underweight and/or have a history of an eating disorder
  • People who have had a recent heart attack, experienced heart failure/Ischemic Heart Disease or have unstable angina.
  • People who are frail or recovering from surgery
  • Older adults >65
  • A person with Type 1 or 2 Diabetes
  • People who are taking insulin or any hypoglycemic agents
  • Women or men undertaking IVF and Fertility Treatment

PS: Do you have any tips for monitoring rapid weight-loss to ensure we are remaining healthy and safe?

Kate: It's a good idea to track weight loss results and weight loss averages to ensure effectiveness of a rapid weight loss program. Average weight loss should be between 1.5kg and 2.5 kg a week so if it was exceeding this you should see the advice of a health professional. You can also record measurements and photographs of your weight loss, to monitor and maintain its effects. People with diabetes or metabolic syndrome should, of course, monitor their blood glucose levels throughout a very low-calorie diet. If you have any of the health conditions listed above, you should also maintain frequent follow up with your GP. It's recommended that a very low-calorie diet is only undertaken for between two and eight weeks — you should consult a health professional or dietician before extending the diet beyond eight weeks.

You can also ensure you stay and feel healthy while dieting for rapid weight loss by managing the symptoms of ketosis appropriately, e.g. headache, lethargy, brain fog in the first three or four days. You should also maximise your water intake and rest time and avoid high-intensity training or exercise.

PS: Does rapid-weight-loss work for everyone?

Kate: Most individuals can participate in rapid weight loss. For those individuals with underlying health conditions or who are identified in the list above, it is best to consult a health care professional first. People with a high BMI along with metabolic issues, such as diabetes, or pre-diabetes, fatty liver and high cholesterol are ideal candidates for a rapid weight loss diet as they have significantly improved health outcomes when they lose 5-10 percent body weight.

PS: If people are looking for ways to lose weight this way, what simple, at-home steps can they take to start their journey?

Kate: The key to successful long term weight loss is dieting the right way, using only whole foods rather than synthetic meal replacements, plus enjoying what you are eating so you are more likely to maintain this new way of eating. Be Fit Food's Be Rapid program consists of meals that each include four-12 vegetables, is nutritionally complete and is designed to help you lose 5kgs in two weeks.

An ideal rapid weight loss diet consists of loads of plant-based foods including low carb vegetables, salads and fruits plus moderate amounts of proteins from meat, chicken, fish and tofu and healthy fats from nuts, seeds and various oils. This low-carb, Mediterranean style of eating helps you feel satisfied while preventing muscle mass losses, plus it stops your metabolic rate from crashing as you successfully achieve your weight loss goals.

PS: Can you recommend specific programs?

Kate: Be Fit Food's Be Rapid Program is a very low-calorie diet consisting of 3 meals and 1 snack per day. The Be Rapid Program provides approximately 820-920 calories and around 40-50g of carbohydrates per day, depending on what meals you choose. Weight loss on the Be Rapid Program occurs through two metabolic processes:

1. Mild Nutritional Ketosis

Mild nutritional ketosis is a state in which our body switches from using sugar (from carbohydrates) as its primary energy source to using our stored body fat. This process creates ketones. Mild nutritional ketosis is a state in which the ketone levels in our body are only slightly elevated (0.3-1.5mmol/l). Typical high fat ketogenic diets induce high levels of ketones, but evidence demonstrates that the weight loss results are the same regardless of whether the ketosis is mild or extreme. Mild nutritional ketosis is also associated with milder side effects.

How do we Induce this state?

Decreasing calories and carbohydrates induces mild nutritional ketosis. This results in a calorie deficit and promotes effective fat loss. The average weight loss of between 1kg and 2.5kg a week can be achieved when replacing all three meals each day with low carb, low-calorie meals from the Be Rapid Program. Our studies show that our customers have lost an average of 5kg in the first two weeks of following this program.*

2. Calorie Deficit

Calories are a measurement of the amount of energy a food provides. Adults typically consume around 2,000-2,500 calories per day on a standard Australian diet. When undertaking the Be Rapid Program we reduce your daily calorie intake to the level of a very low-calorie diet (VLCD) which is approximately 850-950 calories. This forces your body to use its body fat stores for energy. When you eat fewer calories than what your body requires to meet total energy expenditure, then you lose weight.

PS: Who should be consulted before embarking on a rapid weight-loss program?

Kate: Before starting any diet, it is always a good idea to see a dietitian, GP or other health care professional to ensure the diet is suited to you.

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