Sizeism (oppression based on body size) is rarely taken seriously in the United States. Sizeism devalues people whose body type does not meet some socially defined standard based on height, weight or shape — oppression based on weight is a significant area of concern.
Sizeism targets fat people as especially deserving of oppression. Under sizeism, fatphobia (hatred, harassment, exclusion and violence targeting people because of their body weight) is too often viewed as justifiable. That is, fatphobic derision is actually believed by many as a valid motivator for coercing people into losing weight. However, the sizeist claim that fatphobia is in the interest of the target's health is a lie. Sizeism and fatphobia are one thing and one thing only: tools of oppression.
The effects of sizeism and fatphobia include institutional discrimination involving health care, education or workplace situations, such as cases in which people are fired, denied a job or a promotion because of their weight. Interpersonal discrimination includes insults, abuse and harassment from others.
Promoting Anti-Fat Hate
A case study in sizeism and fatphobia is this billboard campaign launched in Jacksonville, Florida, by the nonprofit corporation PETA:

Announcing the campaign was a press release claiming the billboard "reminds people who are struggling to lose weight ... that going vegetarian can be an effective way to shed those extra pounds that keep them from looking good in a bikini." The release cites claims that vegetarians on average weigh less than non-vegetarians before going on to note public health, environmentalism and the treatment of nonhuman animals as other reasons to "go vegetarian." The release then finishes by quoting Tracy Reiman, an executive vice president at PETA, as saying, "Trying to hide your thunder thighs and balloon belly is no day at the beach."
While there are valid personal/public health, environmental and nonhuman animal advocacy arguments for adopting a plant-based dietary system, none of these arguments are being made by this campaign. The fatphobia and sizeism used to refer to people who are fat and/or self-conscious about their weight as "whales" and refer to their bodies with terms like "blubber," "thunder thighs," and "balloon belly" needs to be recognized as perpetuating oppression, which has no place in a genuine campaign for the benefits of vegetarianism.
Furthermore, insults and harassment are not valid motivators to get someone to change their behavior, nor should body weight be viewed as simply the result of individual behavior — if weight is even to be viewed as a problem per se. There is no reason to take seriously PETA's claim that the billboard is a reminder to people struggling with their body weight or that the organization is at all sincere about public health, environmental justice, or ending the oppression of other animals. This campaign is apparently little more than a opportunistic excuse to exploit sizeism and engage in fatphobic insults for the organization's own narrow agenda and self-aggrandizement.
Healthy At Any Weight
The fatphobic insults of the PETA billboard campaign frame a vegetarian diet in a very punitive manner that encourages shame and self-hatred. Promoting vegetarianism as a form of dieting in order to look good in a bikini is contrary to cultivating positive, long-lasting changes in the way we meet our bodies' needs. Framing vegetarianism in sizeism and fatphobia is both harmful and counterproductive. Instead, I believe we need to encourage vegetarianism in a way that is anti-sizeist and body positive.
In short, an anti-sizeist, body-positive approach refuses to devalue people because of their weight, size or shape. It recognizes that everybody is deserving of respect.

