Pica, or the compulsion to consume things nowhere to be found on the food pyramid — like handfuls of dirt, stray pieces of jewelry, or a juicy double-A battery — serves as a metaphor for one woman’s struggle against the patriarchy in Carlo Mirabella-Davis ’ “ Swallow .” A bold and unconventional thriller made real by the evolution of lead actress Haley Bennett (a prize winner at the Tribeca Film Festival) from porcelain housewife to jagged-edged reactionary, this striking debut (not counting earlier shorts or co-directed behind-the-music doc ”The Swell Season”) ignores the medical side of the eating disorder in favor of a far more radical psychological reading.

While not as graphic as 2013 German shocker “Wetlands” (with its grimy public toilet seats and queasy scenes of tampon swapping) nor as gory as 2002’s “In My Skin” (which took the concept of “cutting” to extremes), “ Swallow ” adopts the same basic strategy as those films, using a squirm-inducing disorder to knock audiences out of their comfort zone, then hitting them with a uniquely feminist critique of the social conditions that caused it. That approach — coupled with the twist “Swallow” expects audiences to stomach in its last few minutes — is sure to be controversial, but undeniably powerful, and ought to ensure sufficient notoriety for the film to break through the crowded indie marketplace.

Is it exploitative? Yes, to an extent that’s true. In the wake of “Us,” when people with spasmodic dysphonia objected to the way actress Lupita Nyong’o’s referenced the neurological condition in creating her character’s uneven-sounding voice, it’s important to acknowledge that writer-director Mirabella-Davis is misrepresenting pica to serve his own purposes. But, as in such Alfred Hitchcock classics as “Spellbound” and “Marnie,” with their facile psychoanalytic interpretations of compulsive and/or hysterical behavior, the approach can be quite effective in revealing the gender dynamics of the times.

Certainly, with “Swallow,” that’s the point. Delving into the subconscious of a woman rendered powerless by an outwardly ideal marriage, the film opens, quite tellingly, on the back of its protagonist’s neatly coifed head. From this angle, we can only guess what Hunter (Bennett) is thinking, but even studied face-on, whether the character is alone or role-playing for the benefit of her Ken-doll husband, Richie (Austin Stowell), and well-to-do in-laws (David Rasche and Elizabeth Marvel), we’re confronted by the inscrutability behind her neatly made-up facade.

What an apt challenge to put to audiences in a film committed to exploring the ugliness roiling beneath the surface — of Western culture, of traditional gender roles, of the institution of marriage. Superficially, the movie looks elegant and almost catalog-perfect (for which DP Katelin Arizmendi deserves high credit), though Nathan Halpern’s discreetly cautionary score sends subliminal cues to the contrary. Meanwhile, a recoil-inducing cut from Hunter unpacking her cosmetics to a lamb having its throat slit for dinner puts audiences on edge within the film’s early getting-to-know-you stretch, as if to say, “Don’t get too comfortable.”

Bennett delivers a masterful performance of micro-calibrated precision, in which Hunter presents herself as happy, but seems far away in social situations, a lifelike doll waiting to be called upon. She embodies an old-fashioned, mid-20th-century ideal of doting passivity, reminiscent of January Jones in early seasons of “Mad Men,” where the happy homemaker’s true desires are so carefully masked as to be undetectable at first. But the movie also allows audiences to see Hunter when no one else is watching, preparing her husband’s dinner or designing the room that will serve as nursery to their child.

Yes, Hunter is pregnant — a state that has been known to trigger pica for some, and in which Mirabella-Davis sees a host of anxieties that threaten to overwhelm what little control Hunter feels over her situation. One afternoon, when no one is looking, she takes a marble, places it on her tongue, and rolls the tiny glass sphere around her mouth before swallowing — the way a child might savor the sacrament of her First Communion. Except that Hunter also takes note of its exit, retrieving the marble when it passes a day or two later.

What is going on here? And why, when she finds a shiny silver thumbtack while vacuuming, would she feel tempted to repeat the experiment? Another director — someone with a more overtly provocative, Chuck Palahniuk-like sensibility — might have been tempted to emphasize the gore. Instead, Mirabella-Davis allows our imaginations to do most of the work, encouraging a certain distinctly perverse sense of humor, laced with the undercurrent of tragedy tied up in the reason for Hunter’s behavior.

On repeat viewing, once audiences have gotten the lay of the land, I suspect that “Swallow” is actually highly amusing to watch. For example, there’s an almost diabolical cleverness behind the idea of Hunter getting busted for her shameful habit during the course of her neonatal ultrasound, which reveals something else inside: a small collection of objects that must have been incredibly uncomfortable to ingest.

In the real world, some medical authorities associate pica with iron deficiency, among other theories — although in Hunter’s case, each wince-inducing item she swallows seems almost like an act of aggression against the fetus growing inside her. At a certain point, the movie doesn’t even have to depict her behavior anymore; simply showing the thingamabobs that have passed through her intestine is enough to make us wince. That’s a powerful kind of connection between audience and character with which to enter the film’s final stretch, and a bond that we must feel in order to understand and forgive the cathartic purge still to come.

Dramatically speaking, “Swallow” defies gravity: What goes down must come up. Sooner or later, insights into Hunter’s motives are sure to surface, whether in conversations with her less-than-ethical therapist (Zabryna Guevara) or via a direct confrontation with a problematic man from her past (Denis O’Hare). By the end, characters who initially seemed so simple have taken on startlingly different personas, revealing the true face of an oppressive system in the process — one in which men make the rules, and can institutionalize those who don’t conform. But no one changes more than Hunter. Whether or not she understands the compulsion, each and every object she puts into her mouth is a choice, reclaiming her independence any way she can.