Hunger resulting from inadequate access to available food is formally known as “resource-constrained hunger,” a condition where people experience discomfort, weakness, illness, or pain from prolonged involuntary lack of food caused by economic or social barriers. The U.S. Department of Agriculture distinguishes this from ordinary hunger by defining it as a consequence of food insecurity that goes beyond the usual uneasy sensation of missing a meal. In 2024, roughly 673 million people worldwide experienced this kind of hunger, and 18.3 million U.S. households dealt with food insecurity at some point during the year.
Food Insecurity vs. Hunger
These two terms are related but describe different things. Food insecurity is a household-level economic and social condition: limited or uncertain access to enough food. Hunger is what happens inside an individual’s body as a result. You can be food insecure without going hungry on a given day, perhaps by switching to cheaper, less nutritious meals or skipping variety in your diet. But when food insecurity becomes severe enough, it produces the physical sensation of hunger along with its cascading health effects.
Before 2006, the USDA used the phrase “food insecurity with hunger” to describe the most severe category. An independent panel of experts recommended separating the two concepts, since hunger is a physiological experience that’s difficult to measure through household surveys. The label changed to “very low food security,” but the reality it describes is the same: people going without food because they can’t afford it.
How Food Security Is Measured
The USDA classifies every U.S. household into one of four categories based on a standardized survey. At the top is high food security, where a household reports no problems accessing food at all. Marginal food security means one or two signs of worry, like anxiety about whether food will last until the next paycheck, but little actual change in what people eat.
The two levels that qualify as food insecurity are more concerning. Low food security means a household has reduced the quality, variety, or desirability of their diet but hasn’t significantly cut how much they eat. Very low food security means eating patterns are actively disrupted and food intake is reduced. This is where resource-constrained hunger lives.
The survey itself asks straightforward questions. Respondents are asked whether statements like “We worried our food would run out before we got money to buy more” or “We ate less than we felt we should because there wasn’t enough money for food” were often true, sometimes true, or never true over the past 12 months. For households with children, additional questions ask about relying on a few kinds of low-cost food to feed kids or whether children weren’t eating enough. A scoring system tallies the responses: households without children scoring 6 or higher out of 10 are classified as having very low food security, while households with children need a score of 8 or higher out of 18.
What It Does to the Body
When the body is deprived of adequate food over time, it activates survival mechanisms at the cellular level. One key response is a process where cells break down and recycle their own components to generate energy. This directly influences the hormones that regulate appetite, particularly ghrelin (which signals hunger) and leptin (which signals fullness). Prolonged disruption of these hormones can dysregulate appetite permanently, making it harder for the body to accurately gauge when and how much to eat even when food becomes available again.
The health consequences extend well beyond feeling hungry. Food-insecure people tend to rely on cheaper, calorie-dense foods that are more readily available than healthier alternatives. This pattern increases the risk of obesity, type 2 diabetes, hypertension, and other chronic diseases. It’s a counterintuitive reality: people who can’t consistently access enough food are often at higher risk for conditions associated with poor diet quality rather than simply wasting away. Researchers have documented a clear link between food insecurity and multimorbidity, the presence of multiple chronic conditions at once, driven largely by the inability to maintain a nutritious diet.
Hidden Hunger
Even when people get enough calories to avoid obvious starvation, they may still lack essential vitamins and minerals. This is called “hidden hunger,” and it’s especially common in low- and middle-income countries. The most widespread deficiencies are in iron, vitamin A, vitamin D, iodine, and zinc. A person with hidden hunger may not look malnourished, but the long-term effects include weakened immune function, impaired growth in children, and increased vulnerability to disease. It’s a form of malnutrition that calories alone can’t fix.
Effects on Children’s Development
Children are particularly vulnerable to the effects of inadequate food access. Research tracking children over time has found that those in food-insecure households had significantly lower IQ scores and higher levels of behavioral and emotional problems by age 12 compared to their food-secure peers. The picture is nuanced, though. When researchers accounted for household income and the broader home environment, differences in IQ and behavioral problems were largely explained by those factors rather than food insecurity alone. In other words, food insecurity rarely exists in isolation. It clusters with poverty, housing instability, and other stressors that together shape a child’s development.
What food insecurity does appear to contribute independently is emotional distress. Even after adjusting for income and home environment, food-insecure children showed higher levels of emotional problems. The uncertainty of not knowing whether there will be enough to eat creates a specific kind of chronic stress that weighs on kids in ways that go beyond what poverty alone predicts.
Mental Health and Chronic Stress
The psychological toll of food insecurity is substantial and well documented. Not having reliable access to food creates persistent anxiety, affects emotional stability, and erodes overall psychological wellbeing. This isn’t just about the discomfort of being hungry. It’s the stress of rationing, the shame of not being able to feed a family, and the constant mental math of stretching limited resources.
Food insecurity intersects with structural inequality, racism, and systemic barriers to resources like affordable housing, childcare, and livable wages. These overlapping pressures create what researchers describe as toxic stress and chronic trauma that can perpetuate cycles of disadvantage across generations. A parent dealing with food insecurity is simultaneously more likely to be managing unstable housing, inadequate healthcare, and the compounding mental health effects of all of these at once.
How Many People Are Affected
In the United States, 13.7 percent of households, about 18.3 million, experienced food insecurity at some point during 2024. Households with children were hit harder: 18.4 percent (6.7 million households) were food insecure. In 3.3 million of those households, both children and adults experienced food insecurity. About 751,000 children, roughly 1 percent of all children in the country, lived in households where at least one child experienced the most severe category of very low food security.
Globally, an estimated 673 million people faced hunger in 2024, representing 8.2 percent of the world’s population. That figure was down slightly from 688 million in 2023. But the broader measure of moderate or severe food insecurity, which captures people who may not be starving but face real constraints on accessing adequate food, affected 2.3 billion people, or 28 percent of the global population. Hunger declined overall but rose in Africa and western Asia, according to a 2025 UN report.
Why “Access” Is the Key Word
The specific phrasing of this concept, hunger from inadequate access to available food, highlights something important. In most cases, the food exists. Grocery stores are stocked. The problem is that people can’t reliably get to it or afford it. Barriers include low income, living in areas with few nearby food retailers, lack of transportation, and the higher relative cost of nutritious foods like fresh produce, lean protein, and whole grains compared to processed alternatives. This is why solutions focus not just on food production but on distribution, affordability, and the economic conditions that determine who eats well and who doesn’t.