Case studyMr Mohan is a 40-year-old gentleman who walked into my clinic with complaints of excess weight. He is 163 cm (5.35 feet) tall and weighs 100 Kg with a BMI of 37.6. His weight was 70 kg about 15 years ago, at the age of 25 when he joined an IT company as a software engineer. His job involves sitting in front of a computer for about 8 to 10 hours a day. He does not find time to exercise. .He eats a late dinner which is usually heavy and ends up watching lV for a couple of hours or spending time on social media as he finds it relaxing at the end of long hours of work. He drinks alcohol usually during weekends and spends his Sundays mostly sleeping to catch up on his weekday sleep deprivation.He sleeps only 5 hours every night during the week. He has the habit of munching on chips or other sugar-rich bakery items while watching 1V at night. With the COVID pandemic and lockdown, his working hours have increased from 10 to almost 12 hours as he is working from home. Sometimes he has to do night shifts as his clients are based abroad.The gentleman described above is a typical person that most physicians encounter in their practice on a day-to-day basis. Some are serious about following a healthy lifestyle to shed weight while others find it very hard to change. Few are successful in losing weight by following the right balanced healthy diet, however soon fall off the wagon and end up regaining the few lost kilograms. This article will briefly discuss the basics that one should know to lose weight, including what happens after initial weight loss and tips to maintain a healthy weight in the long term.Determining the bodyweightExcessive eating is a common problem worldwide. Body mass index or BMI is calculated using the height (in meters) and weight (in kilograms) of an individual. It is expressed as weight in kilograms divided by height in square meters. For Asians, a BMI of 22.9-27.5 falls under the overweight category and a BMI of 27.5 and above falls under the obesity category. With a BMl of 37.6, our person Mr Mohan falls in the morbidly obese category.The risks aheadBoth overweight and obese individuals are prone to several comorbidities secondary to excess fat deposition, especially in the waist and the abdomen. These comorbidities include Diabetes, obstructive sleep apnoea (causing excessive snoring and fragmented sleep), elevated blood pressure and cholesterol levels. A weight loss of at least5 per cent of the total body weight can reduce or prevent individuals from developing comorbidities.The mechanism of weightSeveral factors influence body weight like age, gender and sleep. Research studies have shown that males tend to lose more weight when compared to females because of more muscle mass. Slowing of metabolism happens with age and hence it is harder to lose weight as one gets older.Sleep deprivation causes craving for calorie-dense food and increased exposure to hormones like ghrelin resulting in weight gain. Also, certain medications like anti-psychotics and steroids cause weight gain. Similarly, some medical conditions like hypothyroidism and Cushing's syndrome also cause weight gain.Education, followed by practising the knowledge obtained, is the key to produce a good result. This is possible and made relatively easy with a team of physicians, nutritionists and personal coaches along with family support.Ideal weight loss is losing about 0.45-0.9 Kg per week. Anything above this falls under the fast weight loss category.Slow weight loss is better as the individual does not follow a crash diet and hence in the long term, can continue with this lifestyle of moderate exercise and a sustainable diet. After successfully losing weight initially, then the weight stabilises or plateauing of weight loss happens.Achieving weight lossDietWeight loss is achieved when fewer calories are consumed and more calories are burnt with increased physical actMty like exercise, causing a negative energy balance. To obtain energy, the body utilises the glycogen stores or the energy reserve from our body. This causes a breakdown of glycogen.Loss of weight can be achieved through a diet rich in whole grains, vegetables, fruits, nuts and in the case of non-vegetarians lean meat like chicken, fish. This should be accompanied by behavioural changes likemunching on healthy alternatives like carrot or nuts instead of chips or junk food, lifestyle modification (avoiding alcohol or drinking in moderation, quitting smoking and sleeping for at least 7-8 hours every night) and exercise. When these fail, medications and bariatric surgery are recommended to support therapy.There are different types of diet such as Mediterranean diet, ketogenic diet, low carbohydrate diet and intermittent fasting diet that have been found to aid weight loss. Irrespective of the diet, individuals do lose weight. This loss of weight is proportional to the baseline body weight. In other words, the heavier the person is before starting the diet, the more he or she loses when compared to a relatively less heavy person.ExerciseIncreased physical activity both in the form of aerobics and strength training is encouraged. Aerobics (including brisk walking for 45 minutes per day, cycling and swimming) help in burning calories.Strength training helps to build muscle mass, which for the same amount of activity burns more calories. A protein-rich diet also helps with building muscle mass.After the initial weight lossThere are several reasons for plateauing of weight loss including slipping back to the previous lifestyle and drinking alcohol which increases calorie consumption, stress leading to secretion of cortisol, fatigue and sleep disturbance. Portion control is very important while following a diet. One of the reasons for plateauing is loss of portion control and rewarding more often with calorie-dense food. Hence, maintaining a diary will help to keep track of not only diet but also the precipitating factor that causes the slipping.Even if the individual does not lose weight, he or she should not get discouraged and should continue with the diet and physical activity because this will at least prevent additional weight gain. Hence, positive thinking plays an important role in getting back on track.Meal replacement and weight lossWeight loss can be achieved by meal replacement therapy which means substituting a meal with protein and fibre rich snacks or drink. As per Diabetes Remission Clinical Trial (DiRECT), Type 2 Diabetes was reversed successfully in individuals with a weight loss of about5-10 Kg with the help of meal replacement therapy and continued to stay Diabetes free at the end of two years, as long as they maintained the weight loss.To concludeTo summarise, ideal weight loss of 0.45-0.9 Kg/week is possible with a healthy balanced diet, increased physical activity with healthy lifestyle habits including about 7 hours of sleep and good stress management. To avoid plateauing of weight loss which usually happens after 2 to 3 months of the initial weight loss, maintaining a diary will help to find the pitfalls and bring the person back on track or at least prevent him or her from gaining more weight. Dr Suganthi Kumaran is a consultant physician.