These foods are typically high in fibre and have a low glycaemic index. Calories are an important component of food and everything we eat has calories. Calories are of two types. One is empty calories which don't have much nutritive value but just has calories and promotes weight gain. Foods with high fibre and water content usually have fewer calories and we need more energy to digest them, these are called negative calorie foods. These foods help to lose weight as they are not only low in calories but also help to burn out more calories than others. Most negative calorie foods are plant-based.
Soumita Biswas, Chief Nutritionist, Aster RV Hospital, shares the following 10 negative calorie foods:
* Celery: It contains 16 kcal/100g. It is rich in fibre, vitamin A, C and Folate. It is one of the most popular negative food items as most of its calorie value is stored in cellulose. Our body receives very few calories from celery as it is full of undigested fibre.
* Berries: Colourful berries such as blueberries, strawberries, raspberries typically contain just 32 kcal for a half-cup quantity. Berries are called negative calorie foods because of their low glycaemic index and their protein content. It also contains antioxidants, which protects us from various cancers.
* Tomatoes: It has 19kcal/100g. Apart from its water content, it is an excellent source of fibre, potassium and vitamin C. Tomatoes also contain lycopene, an antioxidant known to protect us from skin cancer.
* Carrots: They contain 41 kcal/100g. Its vitamin A content is good for the eyes. Carrot fibre content keeps the stomach full for a longer time thus helps in weight loss.
* Cucumber: It contains 15 kcal/100g. This vegetable has high water content which is great to satisfy thirst along with providing all the necessary vitamins and minerals. The water content present in cucumbers is great for hydration. Along with quenching thirst, this fruit provides dietary fibre and is good for irritable bowel syndrome and diabetic patients.
* Watermelon: It has 30 kcal/100g. Some of the benefits of watermelon rind include a healthy heart, provide hydration and regulation of blood pressure. Additionally, watermelon seeds also have many health benefits starting from the prevention of anaemia to immune-boosting properties. The water content present in watermelon and vitamins A, B6, C along with lycopene act as an immune-boosting food.
* Apple: It provides 52 kcal/100g. Apple contains a good amount of antioxidants, vitamin C and fibres. Apple's high fibre content helps in weight loss and it also helps to boost cognitive performance. Quercetin, an antioxidant present in apples, is also associated with lowering the risk of type 2 Diabetes.
* Broccoli: It contains 34 kcal/100g. Its vitamin A content improves vision. Calcium, Phosphorus, vitamin K content is essential for healthy bone development. Iron and folic acid help to prevent anaemia. Kaempferol, a flavonoid present in broccoli, has anti-inflammatory properties. Broccoli is also rich in Alpha linolenic acid (ALA) which is crucial for brain growth and development.
* Zucchini: It contains about 17 kcal/100g. It is packed with many important vitamins, minerals and antioxidants. This has a high fibre content and a low-calorie count. Fibre plays an important role in digestion. Zeaxanthin, present in Zucchini, plays an important role in preventing oxidative stress and improves eye health.
* Lettuce: It provides about 15 kcal/100g. Its vitamin C, Calcium, vitamin K, vitamin A content helps in boosting immunity. The fibre content of lettuce helps in weight loss. It is also associated with a healthy heart and maintaining eye health.
Are there any side effects?
There is no evidence that eating negative calorie foods leads to side effects. However, directly eating low amounts of calories is not advised if you are not under the supervision of a dietician. The calorie requirement to reduce weight is individualised. The requirement varies depending on the person's height, weight, BMI, BMR, and physical activity.
These foods can be added to our daily diet as snacks or cooking ingredients. Cucumber, tomatoes, carrots and lettuce can be used in various salads. Berries, apple or watermelon fruit can be used as a mid-morning or evening snack. Broccoli, zucchini or lettuce can be used in various preparations during cooking.