Weight management and its correlation to cancer, diabetes and heart disease


Obesity is not just a disease. It is a marker of an individual’s overall health.

Most importantly, obesity can mean an increased risk of cancer, diabetes and heart disease.

Zhaoping Li, MD, chief of the division of clinical nutrition at UCLA Health, said understanding our body and managing our weight can help us significantly lower the risks of all three ailments.

“If you are overweight, it is a symptom showing that several things have gone wrong,” Dr. Li explained. “Also, it will most likely get worse if you don’t do something about it. That’s what the weight problem is telling you.”

There are different levels of obesity, identified by body mass index (BMI) – a measure of body fat based on a person’s height and weight.

Weight management is a key component for disease prevention.

Obesity and cancer

The Centers for Disease Control and Prevention (CDC) cited in a recent publication that being obese increases the risk of getting 13 types of cancer, which combined make up 40% of all cancers diagnosed in the United States each year.

The CDC has said that avoiding tobacco and keeping a healthy weight are the two most important factors to reducing your risk of cancer.

“Obesity is definitely associated with breast cancer and prostate cancers,” Dr. Li said. “Liver cancer has a lot to do with fatty liver. That is also a part of obesity.”

Dr. Li said fatty liver can lead directly to cancer or to cirrhosis, scarring of the liver caused by liver inflammation. When the liver is damaged, it tries to repair itself and scarred tissue forms. The more scarred tissue the liver accumulates, the less liver cells are able to function.

Obesity and heart health

Poor weight management can also have an impact on heart health. Obesity can increase the risk of developing cardiovascular disease (CVD) by damaging the heart structure and affecting the hemodynamics of the heart.

Hemodynamics refers to the flow of blood through the arteries and the mechanics of the cardiovascular system.

Though much emphasis has been placed on eating low-fat diets when it comes to heart health, Dr. Li suggested we also need to watch carbohydrate levels and increase vegetable/fruit intake.

“You don’t want to consume too many carbs because that can increase the risk of heart disease,” she said. “Also, some people are trying to be careful by not eating fatty foods, meanwhile they’re ignoring their carb intake.”

Daily exercise such as running or walking is a key component to overcoming obesity.

Excess carbohydrates can lead the liver to produce fat and cholesterol which can deposit in your blood vessels, making it hard for blood to flow through your arteries. The deposits can trigger blood clots which can lead to heart attacks or strokes.

Dr. Li pointed to a mistake people sometimes make at breakfast.

You may be familiar with TV commercials showing a bowl of cereal next to a plate of toast, a glass of milk, a glass of orange juice and some fruit accompanied by a voiceover stating it was all a delicious part of a “complete breakfast.”

As it turns out, those images do not represent a healthy breakfast.

“Eating cereal with orange juice is not a good combination,” Dr. Li said. “It’s too many carbs. Your body will take the excess and turn it into fat and cholesterol.”

Dr. Li explained that the body only needs on average of 8 grams of carbs per hour and that a slice of bread by itself is good for up to four hours. If you eat an excessive amount of carbohydrates, your body will convert it to triglycerides, which is a form of cholesterol.

According to Dr. Li, 80% of the cholesterol inside you is made by your liver, not food. Adding a high cholesterol diet to that will cause problems. This is why it is important to know the ingredients of the food you eat.

Many people are unaware that a “nutritious” drink such as orange juice is high in carbohydrates. In addition, buying at a store most likely means that it is processed. Juicing oranges at home on your own is much healthier.

There are certain foods that can help lower cholesterol and be part of your healthy dietary pattern:

  • Almonds
  • Avocados
  • Olive oil
  • Fish (omega-3 fatty acids)
  • Chicken
  • Turkey
  • Whey protein
  • Mixed plant-based protein
  • Vegetables
  • Oatmeal

Obesity and diabetes

Obesity is the No. 1 risk factor when it comes to type 2 diabetes which, in turn, is a risk factor for cardiovascular disease.

“Diabetes stems from a mismatch of what you eat and what your body needs,” Dr. Li said. “In another sense, your body becomes intolerant and cannot handle any additional carbohydrates.”

Glucose is a sugar that comes from the food we eat. Our bodies use it for energy. When the glucose moves into the bloodstream it is called blood glucose, or blood sugar.

When the food we have eaten reaches our stomach, digestive enzymes break the starchy food down into tiny pieces, at which point the glucose is released and moves into our intestines. It is then passed into our bloodstream where insulin helps it move into our cells. Foods that are high in carbohydrates such as potatoes, bread and fruit give us the most glucose.

Diabetes develops from high levels of glucose in the blood and not enough tissues responding to insulin to store excess sugar as fat. Insulin is a hormone that helps move glucose into tissues to be used as energy.

However, type 2 diabetes is reversible with a focus on the correct diet.

Frequently eating a colorful plate of fruits and vegetables, coupled with exercise, can make weight management a smooth process.

Nutrition is key

“Type 2 diabetes can be reversed if people with diabetes begin to watch their diet,” said Dr. Li. “Nutrition is not just for prevention. It is also a treatment strategy.”

Dr. Li said there are three keys to managing our diet in order to reduce the risk of disease:

  • Eat natural foods. Processed foods pose major problems when it comes to weight management because of their unhealthy levels of added fat, sodium and sugar.
  • Don’t overeat. Even with nutritious foods, it’s important that you only eat what your body needs.
  • Diversify your plate. The more colorful your plate is with fruits and vegetables, the healthier the plate is.

Increasing your meals with a high variety of fruits and vegetables, while eliminating sugars and processed foods, is vital for regulating your weight and significantly reducing your chance for disease. Each fruit and vegetable color represents nutrients that fight off various disease-causing agents.

“You want to add diversity to your plate. You can have carrots, which are a good source of beta carotene and you can have tomato, which is a great source of lycopene,” Dr. Li said.

“However, before you talk about what to eat, you have to have the right mindset to take care of your body and health,” she said. “Having the right mindset begins with a commitment to eating whole foods, getting plenty of exercise and rest, and coming in to see one of us to eliminate any confusion you might have about nutrition.”

To learn more about dieting and weight management, visit the UCLA Center for Human Nutrition.