In an interview with People, the singer and daytime talk show host said she had lost weight as part of a new well-being routine.
The Since U Been Gone singer said she did lots of walking, ate a healthy mix of foods as well as enjoyed occasional treats.
According to Healthline, one of the most effective ways to reduce belly fat is to regularly take part in aerobic exercise, such as walking.
As little as one hour per day, at any pace, can help to shed pounds when combined with healthy eating.
Physical activity has also been shown to improve your mind and decrease feelings of stress, depression and anxiety.
Kelly said: “Walking in the city is quite the workout. I’m really into infrared saunas right now. And I just got a cold plunge because everybody wore me down.
“I dropped weight because I’ve been listening to my doctor, a couple of years I didn’t.”
The singer added that she enjoys a protein-rich diet which includes lots of meat as well as treats such as frozen yoghurt.
Protein-rich foods include chicken, lamb, beef, yoghurt and cheese, especially cottage cheese.
According to Healthline, protein reduces appetite which helps you to eat fewer calories.
They explained: “Due to the thermic effect and several other factors, a high protein intake tends to boost metabolism too.
“It makes you burn more calories around the clock, including during sleep. A high protein intake has been shown to boost metabolism and increase the amount of calories burned by about 80 to 100 per day.”
Combining protein with other essential nutrients also helps to increase satiety, resulting in less consumption of other foods.
Kelly also explained how she enjoys infrared saunas, and whilst these aren’t directly associated with weight loss, they can have some health benefits.
According to Healthline, they can help to detoxify the body, while cold plunges may help to lower body fat due to their effect on blood sugar regulation.
However, overall, maintaining a healthy diet and exercising is key to any weight loss, consuming fewer calories than you are burning.
Diets that are too strict can be difficult to stick with long-term, so enjoying a treat now and again should be incorporated.
Many experts recommend the 80/20 rule which means you eat healthily 80 percent of the time and enjoy treats during the remaining 20 percent.
Another singer who has also lost weight in recent years is Adele who shed seven stone through exercising.