Can Long-Term Weight Loss Diets Lower Your Colon Cancer Risk?

Colorectal cancer is one of the most common types of cancer in the world. Ferlay J et al. say that GLOBOCAN 2012 says that it is the second most frequent cancer in women and the third most common cancer in men, with men getting it a little more often. The numbers are worrisome, as they show how closely chronic disease is tied to lifestyle choices, including nutrition, obesity, and exercise. Obesity is becoming a major health problem around the world and is one of the main risk factors for adenomas and colorectal cancer. Extra weight on the body can lead to a number of long-term health problems, including heart disease, diabetes, and several types of cancer.

The National Family Health Survey (NFHS-5, 2019-21) found that almost one in four men and women in India are obese. The Indian Council of Medical Research did a study across the country and found that one in three adults in India, or about 35 crore people, has abdominal obesity. One in four adults, or 25 crore people, has general obesity, and one in five adults, or 21 crore people, has high cholesterol. These habits immediately raise the risk of colon cancer since being overweight around the stomach, in particular, makes the body more likely to acquire cancer.

Why Losing Weight Is Important

Doctors often tell overweight and obese patients to lose weight, but it has long been unclear whether lowering weight lowers the risk of colon cancer. Obesity makes the body less sensitive to insulin, elevates levels of growth hormones, and causes inflammation. All of these things can help tumours grow in the colon. On the other hand, losing weight improves metabolic balance and lowers the amount of fat that builds up around the colon. Both of these things are thought to lower the risk of cancer. A diet low in fat stops cholesterol from building up in the arteries and increases blood flow to the colon. This limits one of the ways that tumours form.

Data From Long-Term Studies

The most convincing proof comes from large-scale screening trials. Researchers looked at data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, which included 154,942 people in the U.S. aged 55 to 74 between 1993 and 2001. They wanted to see how weight changes over time affected the risk of colorectal adenoma. People who shed at least 1.1 pounds every five years had a 46 % decreased chance of acquiring colorectal adenomas than people whose weight stayed the same. This decrease was more pronounced among persons who were initially overweight or obese. Conversely, those who saw weight gain above 6.6 pounds per five years exhibited an increased propensity for adenomas. These results were more pronounced in men than in women, indicating potential sex-based biological disparities.

Thus, living a healthy lifestyle and keeping your weight in control lowers your chances of diabetes and heart disease. It may also lessen your risk of precancerous polyps evolving into colon cancer.

The Link Between Obesity And Colon Cancer

Fat that is too much around the stomach is active in the body. It produces chemicals that induce long-term inflammation, disrupt hormone levels, and make it easier for cancer cells to grow. Obesity also makes the blood have more insulin and insulin-like growth factors. High levels of these hormones make cells proliferate, and in the colon, this makes it more likely that polyps may turn into cancer.

The connection between obesity and colon cancer is especially worrying in India, where the number of obese people has risen quickly. According to the World Obesity Federation, India has one of the highest yearly rates of childhood obesity in the world. In the last 15 years, childhood obesity has doubled, and in the last 30 years, it has tripled. COVID-19 made this worse: more people gained unhealthy weight because of lockdowns, less physical activity, and more reliance on processed food.

Colon Cancer Factors In Diet And Lifestyle

There are a few ways of eating that can directly affect the risk of colon cancer:

• Red and processed meat: When you cook meat at high temperatures, chemicals like heterocyclic amines are created that can make cancer more likely. The American Institute for Cancer Research says that people should only eat 12 to 18 ounces of red meat a week.
• Sugar-sweetened drinks: These drinks are known to cause weight gain, which is a risk factor. More research is needed, though.
• Heavy drinking: Especially in men, this is significantly associated with an increased risk of colorectal cancer. Women should only have one drink a day, while men should only have two, according to the American Cancer Society.
• Not eating enough fibre: Fibre helps keep the gut microbiota healthy, lowers inflammation, and helps with digestion. Getting at least 30 grams of fibre every day from whole grains, beans, fruits, and vegetables is linked to a lower risk of colon cancer.
• Low calcium and vitamin D: Not getting enough of these minerals has been related to a higher risk. Dairy products can assist, but you should be careful not to eat too much because that can raise your risk of prostate cancer.

On the other hand, eating more fibre, lentils, lean meats, and moderate amounts of dairy can lessen your risk and help you keep your weight. The American Institute for Cancer Research says that diets high in legumes, such as beans, lentils, and peas, are especially good for you.

Diets That Help You Lose Weight And Prevent Colon Cancer Long-Term

Crash diets or short-term programmes could help you lose weight quickly, but the best way to prevent colon cancer is to make long-term adjustments that you can stick with. Weight cycling, losing and gaining weight repeatedly, has not been studied as much in relation to colon cancer; however, consistent weight loss is better for your health. The PLCO trial findings indicate that even modest and persistent weight loss throughout adulthood substantially decreases adenoma risk.

For those who are overweight or obese, making organised adjustments to their diet, such as eating less fat, more fibre, and avoiding ultra-processed foods, can help them lose visceral fat, speed up their metabolism, and lessen their risk of cancer. Adding exercise to your diet makes these benefits even better because regular exercise lowers inflammation and makes insulin resistance less likely.

India's nutritional changes over the last 20 years show how hard it is. The country went from not having enough calories to having enough, but not everyone has the same access to good food. According to the State of Food Security and Nutrition in the World Report 2024, 55% of people in India cannot afford a balanced diet, and about 40% do not get enough nutrients. Obesity has also grown because it is so easy to get inexpensive, ultra-processed, high-fat, salty, and sugary foods. The World Health Organization says that half of Indians do not get enough exercise, which raises the risk even more.

(By Dr Ashish Gautam, Senior Bariatric, Robotic and Gastrointestinal Surgeon | Medical Director, Dr Gautam Health Care Center and Clinic | Senior Director, Robotic and Laparoscopic Surgery, Max Super Speciality Hospital, Patparganj, New Delhi)

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