Nope. While it is true that some types of cancer are more common among fat people, other types of cancers are less common among fat people.
Moreover, for those cancers that are more common among fat people or have higher mortality rates for fat people, it is unclear whether fatness is the cause of these outcomes or the fact that fat people avoid fat-phobic doctors who provide sub-par medical care, including offering fat people fewer cancer screenings.
Furthermore, all of the evidence linking weight and cancer rates is correlational, and you cannot make causal claims about the association between two variables on the basis of correlational data. This may seem like some kind of nitpicky detail, but it is not. It is literally the foundation of all good science, and people who violate this rule are being sloppy at best and manipulative at worst.
From the National Cancer Institute:
[T]here is consistent evidence that higher amounts of body fat are associated with increased risks of a number of cancers (6), including:
Endometrial cancer: Obese and overweight women are two to about four times as likely as normal-weight women to develop endometrial cancer (cancer of the lining of the uterus), and extremely obese women are about seven times as likely to develop the more common of the two main types of this cancer (7). The risk of endometrial cancer increases with increasing weight gain in adulthood, particularly among women who have never used menopausal hormone therapy (8).
Esophageal adenocarcinoma: People who are overweight or obese are about twice as likely as normal-weight people to develop a type of esophageal cancer called esophageal adenocarcinoma, and people who are extremely obese are more than four times as likely (9).
Gastric cardia cancer: People who are obese are nearly twice as likely as normal-weight people to develop cancer in the upper part of the stomach, that is, the part that is closest to the esophagus (10).
Liver cancer: People who are overweight or obese are up to twice as likely as normal-weight people to develop liver cancer. The association between overweight/obesity and liver cancer is stronger in men than women (11, 12).
Kidney cancer: People who are overweight or obese are nearly twice as likely as normal-weight people to develop renal cell cancer, the most common form of kidney cancer (13). The association of renal cell cancer with obesity is independent of its association with high blood pressure, a known risk factor for kidney cancer (14).
Multiple myeloma: Compared with normal-weight individuals, overweight and obese individuals have a slight (10% to 20%) increase in the risk of developing multiple myeloma (15).
Meningioma: The risk of this slow-growing brain tumor that arises in the membranes surrounding the brain and the spinal cord is increased by about 50% in people who are obese and about 20% in people who are overweight (16).
Pancreatic cancer: People who are overweight or obese are about 1.5 times as likely to develop pancreatic cancer as normal-weight people (17).
Colorectal cancer: People who are obese are slightly (about 30%) more likely to develop colorectal cancer than normal-weight people (18).
Gallbladder cancer: Compared with normal-weight people, people who are overweight have a slight (about 20%) increase in risk of gallbladder cancer, and people who are obese have a 60% increase in risk of gallbladder cancer (19, 20). The risk increase is greater in women than men.
Breast cancer: Many studies have shown that, in postmenopausal women, a higher BMI is associated with a modest increase in risk of breast cancer. For example, a 5-unit increase in BMI is associated with a 12% increase in risk (21). Among postmenopausal women, those who are obese have a 20% to 40% increase in risk of developing breast cancer compared with normal-weight women (22). The higher risks are seen mainly in women who have never used menopausal hormone therapy and for tumors that express hormone receptors. Obesity is also a risk factor for breast cancer in men (23).
Ovarian cancer: Higher BMI is associated with a slight increase in the risk of ovarian cancer, particularly in women who have never used menopausal hormone therapy (24). For example, a 5-unit increase in BMI is associated with a 10% increase in risk among women who have never used menopausal hormone therapy (24).
Thyroid cancer: Higher BMI (specifically, a 5-unit increase in BMI) is associated with a slight (10%) increase in the risk of thyroid cancer (25).
A higher BMI is associated with increased risks of colon and rectal cancers in both men and in women, but the increases are higher in men than in women (18).
In premenopausal women, by contrast, overweight and obesity have been found to be associated with a 20% decreased risk of breast tumors that express hormone receptors (22).
Hmm. Who to trust in this situation? A proven liar with an agenda dedicated to legitimizing the shitty life choices that she and others have made, or the National Cancer Institute?
Hmm. I wonder who is drawing bad conclusions because of ignorance of the scientific method? Is it @bigfatscience, or the National Cancer Institute?
I can’t possibly choose who to believe!