A rapid weight loss diet involves losing more than 2 pounds (lb) or 1 kilogram (kg) a week over several weeks. To achieve this, one must consume very few calories, making it a drastic approach often considered by individuals with obesity who seek quick results. These diets require close supervision by healthcare providers, as rapid weight loss may not be safe for everyone and is intended for short-term use.
Understanding Rapid Weight Loss Diets
Rapid weight loss diets are usually for people who have health problems because of obesity. For these people, losing a lot of weight quickly can help improve:
- Diabetes
- High cholesterol
- High blood pressure
However, individuals who lose weight very quickly are more prone to regaining it compared to those who opt for gradual weight loss through balanced diet changes and regular physical activity. Rapid weight loss can be a significant stressor for the body, leading to a stronger hormonal response.
Types of Rapid Weight Loss Diets
Very Low-Calorie Diets (VLCDs)
VLCDs typically involve consuming very few calories. Most VLCDs use meal replacements like formulas, soups, shakes, and bars instead of regular meals to ensure adequate nutrient intake. VLCDs are recommended for adults with obesity who need to lose weight for health reasons, often before weight-loss surgery. It is crucial to undertake a VLCD under the guidance of a healthcare provider, generally for no more than 12 weeks.
Low-Calorie Diets (LCDs)
LCDs generally allow about 1,200 to 1,500 calories a day for women and 1,500 to 1,800 calories a day for men. An LCD is a better choice than a VLCD for most people who want to lose weight quickly. It may use a mix of meal replacements and regular food, making it easier to adhere to compared to a VLCD, though medical supervision remains essential.
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Time-Restricted Eating
Time-restricted eating limits the number of hours per day that you can eat. A popular strategy is the 16:8 method, where all meals are consumed within an 8-hour period, followed by a 16-hour fasting window. While some studies suggest this method can lead to rapid weight loss, more information is needed to determine if the weight loss is sustained.
Fasting
Fasting, an ancient form of caloric restriction, has gained popularity due to studies showing potential benefits for individuals with diabetes and obesity. The 5:2 system, a popular regimen, involves fasting or VLCD for 2 days a week and normal eating for the remaining 5 days. Diets incorporating fasting can induce rapid weight loss, but safety and sustainability vary.
Fad Diets
Some fad diets severely restrict calories for rapid weight loss, which can be unsafe and unsustainable. People are at risk for regaining weight if they return to old eating habits after stopping the diet. A safe approach for most people involves choosing a diet that promotes a weight loss of 1/2 to 1 lb or 225 to 500 grams (g) a week.
What to Eat on a Rapid Weight Loss Diet
Regardless of the specific weight loss diet, it is important to maintain a healthy and balanced eating plan without excluding any food groups. Incorporate the following:
- Whole Grains: These include foods such as whole wheat, brown and wild rice, oats, and quinoa.
- Dark Leafy Greens: Popular examples include bok choy, arugula, Swiss chard, kale, collard greens, and romaine lettuce.
- Fruits: Low-calorie fruits such as lemons, strawberries, grapefruit, blackberries, blueberries, and pineapples are rich in antioxidants and fiber, promoting satiety.
- Lean Proteins: High protein diets can increase satiety hormones while reducing hunger hormones. Examples include trout, tuna, salmon, mackerel, herring, sardines, and pilchards.
Potential Weight Loss on an 800 Calorie Diet
If your BMI is greater than 30, then very low-calorie diets are generally safe when used under proper medical supervision. Then a very low-calorie diet may result in a loss of 3 to 5 pounds per week, for an average total weight loss of 44 pounds over 12 weeks. The weight loss at week 8 was positively correlated with initial body weight. In the multivariate regression model, adjusted for center, only initial body weight, early weight loss (week 1) and weight loss at week 3 were significant predictors of weight loss outcome at week 8: weight loss (kg) at week 8=0.09+0.046 x baseline body weight (kg)-0.311 x weight loss (kg) at week 1+1.284 x weight loss (kg) at week 3 (R(2)=68%, P<0.0001).
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The 800 Calorie Diet: A Closer Look
An 800-calorie diet is a very low-calorie diet (VLCD) that requires medical supervision. The dramatic calorie restriction can lead to significant weight loss but also carries substantial health risks.
Effectiveness
An 800-calorie diet can result in rapid weight loss, typically chosen by those seeking quick results.
For individuals with a BMI over 30, very low-calorie diets may lead to a loss of 3 to 5 pounds per week, averaging about 44 pounds over 12 weeks. However, it's important to note that even a modest weight loss of 5% of body weight can improve medical conditions like diabetes, high blood pressure, and high cholesterol.
Risks and Side Effects
Following an 800-calorie diet without medical supervision can lead to several health complications:
- Nutrient Deficiencies: A restricted diet may lead to micronutrient deficiencies, impacting bodily functions, energy levels, and cognitive abilities. Research on obese people who followed a low-calorie diet showed they experienced micronutrient deficiencies.
- Metabolic Slowdown: Consuming fewer than 1,000 calories daily can significantly decrease metabolic rate. Studies show that low-calorie diets can decrease the number of calories the body burns by as much as 23 percent. The body lowers its calorie-burning rate to conserve energy, making long-term weight loss more challenging.
- Gallstones: A one-year comparative study in Sweden showed that people on a very low-calorie diet are three times more likely to get gallstones than those who follow a low-calorie diet. When the body experiences a calorie deficit, it starts to break down fat for energy. The liver then secretes more cholesterol and when combined with bile, can form gallstones.
- Bone Density Loss: Diet-induced weight loss can cause a temporary decrease in bone density.
- Other Side Effects: People on a very low-calorie diet for 4 to 16 weeks report minor side effects such as fatigue, constipation, nausea, and diarrhea. These conditions usually improve within a few weeks and rarely prevent people from completing the program. You may also be a lot weaker than before as your body will not have the energy it needs to sustain itself. You may also be feeling constantly nauseated and constipated, if you’re not battling diarrhea.
When followed for a long time, such diets may increase the risk of death due to cardiovascular disease, cerebrovascular disease, and cancer.
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Contraindications
Very low-calorie diets are not recommended for pregnant or breastfeeding women and are not appropriate for children or teens except in specialized treatment programs. They also may not be OK for people over age 50, either, depending on the potential need for medications for pre-existing conditions, as well as the possibility of side effects.
The Importance of Medical Supervision
Healthcare professional can assist in determining the appropriate weight loss plan based on an individual’s specific health background and goal weight. Medical supervision ensures optimal monitoring of nutrient deficiencies, side effects, and plan adjustments. Medical supervision ensures optimal monitoring of nutrient deficiencies, side effects, and plan adjustments. You should only follow one of these diets with the help of your provider.
Sustainable Alternatives for Weight Loss
For most people, it is safest to choose a diet in which you lose a 1/2 to 1 lb or 225 to 500 grams (g) a week. Here are several sustainable approaches to weight loss:
Gradual Calorie Reduction
Instead of drastically cutting calories, aim to reduce your daily caloric intake by 500 to 750 calories. This can be achieved by:
- Tracking your normal eating habits for a week using a calorie counter.
- Cutting 500 to 750 calories from your daily calorie intake via food and drinks.
- Choosing healthier food options and portion sizes.
- If you prefer heavier meals in the morning, try lighter lunches or dinners.
Balanced Diet
Focus on a balanced diet that includes:
- Plenty of fruits and vegetables
- Lean protein sources
- Whole grains
- Healthy fats
Regular Physical Activity
In addition to cutting calories, exercise more. Incorporate both cardio and weight training for at least 30 minutes a day.
Intermittent Fasting
If you are looking for a less aggressive weight loss method, give intermittent fasting a go. Intermittent fasting does not require individuals to limit calorie intake unless they want to, making it a safe weight loss method. Fastic provides an estimated timeline for achieving your goal weight and creates a personalized fasting plan tailored to your unique lifestyle.
Other Diet Approaches
- Small Meals: Consists of eating between 6 to 10 small meals and snacks throughout the day. This methodology allows for the body to have sustained energy levels during the day, diminishing the chances of experiencing feelings of hunger.
- Low-Carb or Keto Diet: Reducing carbohydrate intake while increasing fats and moderate protein consumption can help with weight loss by helping stabilize blood sugar and providing stable energy levels throughout the day resulting in less hunger during the day.
- Plant-Based Diet: Eating plant-based foods such as vegetables, fruits, nuts, and whole grains encourages weight loss and lowers the risk of developing chronic diseases.
Long-Term Weight Management
Once you go off a diet, you need to change your lifestyle, committing to healthy eating and regular physical activity.
Maintenance Phase
The aim of this stage of the diet is to normalise liver and pancreas fat and promote regular insulin response and blood glucose management.