*Review of Food Access in the Shade of Critical Times DOI: http://dx.doi.org/10.5772/intechopen.107041*

levels. At the individual level in the United States, the National Food Stamp Survey in 1996–1997 documents people's answers about their food outlets' distance to their homes [5]. More surveys were developed in 2011 as a food security supplement survey asking if they had enough food in their homes [5]. Another measure that investigates the indirect impact is the distance to food outlets by the Economic Research Service (ERS) 2012 [5]. Further measure at the individual level is the Retail Food Environment Index (RFEI). It is a survey method about people's access to food outlets and their options [5]. Another method of measuring access to food is by the area category location of food outlets and related variables in a neighborhood [5]. In the area category location method, the access to food can be measured by the distance to food outlets, income, poverty rates, and transportation access [5]. These factors categorize tracts or districts from the poorest in healthy options to the most nutritious area. These areas are as follows:

Food desert: This phrase was firstly used in Scotland in the 1990s to define low access to food outlets due to low income [6]. After that, researchers around the world adopted the definition and applied more classifications. It is defined as areas with more than one mile to grocery stores. People living in food desert areas or tracts have limited healthy options with higher prices and limited access to public transportation [7]. The area's residents rely on small stores more than supermarkets because of location availability [7]. These small stores tend to have smaller quantities and higher prices, and fewer fresh options [7].

Food swamp: These areas or tracts have more unhealthy food outlets than healthy food options [8]. These neighborhoods are more likely to be minority and low-income [9]. Several studies proved that fast-food restaurants are concentrated in racial-ethnic minorities' neighborhoods [10].

Food oases: These areas have people with high socioeconomic status and an abundance of healthy food outlets such as supermarkets, grocery stores, farmers' markets, and community gardens [11]. This food access condition is the ideal goal for food access development where people have more options for healthy food.

The influence of food access on people's health and behavior is investigated, and it varies based on income, urbanism, population density, and people's ethnicity. Furthermore, low access to food causes several negative effects on people's health such as delayed childhood development, diet-related diseases, and malnutrition or hypernutrition. These food access areas show different records and impacts on people's lives and health [12]. Factors such as car access and income are the most critical variables in people's access to food [13]. A study in Australia found that financial aid or allowance improved people's access to food [14]. For that, government financial aid and food credits can support people's access to healthy food. People's access to transportation such as busses stations or personal cars improves their nutritional choices. In addition, walking to food outlets is not feasible in different seasons, summer limits food access due to the heat during the day, and winter limits food access due to the extremely cold climate [15]. Lack of access to adequate food is a key factor in some diseases such as obesity, diabetes, hypertension, cancer, and high mortality rates [6]. A study conducted in the United States proved that food swamps can predict obesity more than food deserts, and its prediction becomes more accurate when it is combined with income inequality and low transportation access [9]. Moreover, a study conducted in Australia proved the same hypothesis that access to transportation is more affected by people's access to food than their location in food desert areas [16].

Inadequate distribution of food outlets in urban areas influences people's wellbeing negatively. People's health and wellness are proven to show a negative impact on food access in several studies in the United States and around the world. Several studies found that people with more access to fast food also indicate having higher body mass [17]. A study conducted in Philadelphia, a city ranked as the highest in food scarcity, in the surrounding area by 2 miles of fast-food restaurants, found out that the low access to fresh food sources is associated with a higher rate of health issues such as diabetes, heart diseases, and cancer [18]. A study in California illustrates obesity variation to correlate with food access, but the variation in obesity could be because of people's characteristics and diets [19]. A study compared people in the food desert and found out that people in the food desert showed more chronic kidney disease and hypertension [20]. Moreover, a recent study is conducted by our team in Guilford County in North Carolina on the correlation between accessing food and health issues [12]. Their results illustrate that food deserts show higher mortality rates and higher rates of health issues such as obesity, high cholesterol, and high blood pressure [12]. More studies on the correlation between food distribution and people's health proved a strong correlation with illnesses such as tuberculosis [21].

Furthermore, it is documented that there is a connection between food deserts, low income, low access to transportation, and diabetes [22]. Food and physical activity have a significant impact on predicting children's obesity [23].

More variables or factors influence food access such as ethnicity. In the United States, low access to food areas is in low-income and colored communities [24]. A study illustrated the investigation of people's ethnicity and their food access and choices [24]. The survey results show variation in food access based on ethnicity [24]: less healthy food was consumed more by African Americans; Latino communities have better access to healthy food; and immigrants consumed more fruit, rice, and beans [25].
