Energy balance is integral to reducing the risk of developing many chronic diseases associated with excess body weight, including cancer [10]. Energy intake and daily physical activity are key factors in the regulation of body weight. While there may be some limitations for using BMI as an indicator of “healthy” body weight for adults, the range of 18.4–24.9 kg/m² has been accepted by the healthcare community as a healthy body weight range to reduce risks of comorbidities.

Prior to the development of cancer screening and detection guidelines, many cancer patients were diagnosed with disease in advanced stages [11]. Antineoplastic treatment(s) and the disease itself frequently resulted in inadequate oral intake due to the presence of nutrition impact symptoms such as anorexia, nausea, and early satiety [11]. As a result, involuntary weight loss, malnutrition, and cachexia were common outcomes [11]. Fortunately, advanced technologies and techniques today have helped improve the detection and diagnosis of cancer when it is in the early stages – the stages when it is most treatable and curable.

Currently, there is a global obesity epidemic, and cancer survivors today are more likely to be overweight or obese at the time of their diagnosis [11]. The National Cancer Institute estimates that about 500,000 new cases of cancer will be diagnosed in the USA by 2030 if the current obesity epidemic continues [12]. With this, evidence is emerging that being overweight or obese at the time of diagnosis of certain cancers, such as prostate, endometrial, pancreatic, and esophageal, is associated with adverse outcomes including increased risk of disease recurrence and reduced survival [3].

Traditionally, many cancer survivors experienced unintentional weight loss as a consequence of antineoplastic treatment. Today, many treatment regimens are associated with weight gain. Therefore, survivors who are overweight or obese should be counseled to avoid weight gain during cancer treatment [3, 4]. Furthermore, intentional weight loss posttreatment for cancer survivors who are overweight or obese may reduce not only risk of recurrence but also risk of other health-related conditions such as cardiovascular disease, diabetes, and hypertension.

Red meat (e.g., beef, pork, lamb) is often defined as the flesh from animals that are higher in red muscle fibers than white muscle fibers (e.g., fish and chicken). While there is no standardized definition for processed meats, it is generally accepted that meats preserved through curing, salting, smoking, or the addition of preservatives such as sodium nitrite are usually considered processed [13]. Common processed meats include bacon, lunchmeats such as ham, pastrami, and turkey, as well as sausage. Consumption of red meat reportedly continues to increase both in the USA as well as globally [13].

The 2007 expert report published by the WCRF and AICR recommended limiting the intake of red meat to 18 ounces per week, while processed, charcoaled, well-done, and smoked meats should be avoided altogether [4]. This report also concluded that the consumption of red and processed meats was convincingly associated with the development of colorectal cancer based on the evidence from 16 cohort studies and 71 case-control studies [1]. Furthermore, the 2011 WCRF/AICR continuous update project regarding colorectal cancer further supported the 2007 recommendation [4, 14]. The same report also found evidence to suggest that consumption of red and processed meats may increase the risk for endometrial, esophageal, lung, stomach, pancreas, and prostate cancers; however, the panel determined that the evidence was limited and, in some cases, conflicting. Consistent with the WCRF/AICR expert report, the National Institutes of Health (NIH) and American Association of Retired Persons (AARP) published a study that noted the positive association between red meat/processed meat intake and colorectal cancer [15]. Additionally, a meta-analysis published by Alexander et al. that included 28 prospective studies also found a significant association between colorectal cancer and processed meat intake (high compared with low intake, 1.16; 95 % CI, 1.10, 1.23) [16]. However, it was concluded overall that given the weak magnitude of the evidence and lack of standard definition describing what constitutes “processed meat,” the current data based on epidemiologic studies may not be sufficient.

While the precise etiology of why consumption of red and processed meats increases the risk for cancer is unclear, a mechanistic role has been proposed for the production of heterocyclic amines (HCA), polycyclic aromatic hydrocarbons (PAH), and N-nitroso compounds and the presence of heme iron [13]. How meat is cooked appears to be the tipping point, since meat cooked to well done over high temperatures results in the formation and deposition of PAHs in the meat. Additionally, HCAs are produced when the amino acids, creatine, and sugars found in the muscle tissue of meat react at high temperatures. Based on animal studies, these compounds are considered carcinogens. The presence of iron within the myoglobin of the meat also increases nitrosamine formation when cooked, causing damage to DNA. In addition, the nitrates/nitrites and salt used to process meat contribute to nitrosamine production and also act as carcinogens in animals [15].

While research has shown an association between the consumption of red and processed meat and colorectal cancer, information remains somewhat inconclusive in respect to red meat and processed meat consumption with other cancer diagnoses [3]. However, evidence indicates that the risks of consumption outweigh the benefits in respect to other cancers, as well as all-cause mortality. To confirm this statement, Pan et al. performed a prospective, observational study of 37,698 men and 83,644 women and found that a 1-serving per day increase in red meat consumption was associated with an increase in total mortality and cancer mortality [17]. In a meta-analysis performed by Larsson, Orsini, and Wolk, an increased consumption of 30 g/day of processed meat was associated with a statistically significant 15 % increased risk of stomach cancer [18]. An increased 16 % risk of lung cancer was also evident within a cohort of approximately 500,000 individuals with the highest intake levels of red meat and processed meat [19]. Because the body of evidence currently available reflects a potential association between red and processed meat consumption, the WCRF/AICR guidelines recommend that individuals who consume red meat limit their intake to no more than 18 ounces/week and consume very little – if any – processed meats [4, 14].

Regular, physical activity is associated with a multitude of benefits for all children and adults and, as such, is widely recommended by health organizations worldwide. Physical activity is associated with reducing the risk for the most common chronic diseases including cardiovascular disease, type II diabetes, and hypertension with evidence accumulating that risk for some types of cancers can also be reduced [3]. The results from prospective observational studies reflect that regular physical activity also can be beneficial for cancer survivors during and posttreatment for improving aerobic fitness, endurance, and quality of life while reducing fatigue, depression, and insomnia. Moreover, a lower risk of mortality associated with higher levels of moderate-to-vigorous physical activity has been reported for breast, prostate, and colorectal cancer survivors [3]. To highlight this, a meta-analysis and systematic review published by Schmid and Leitzmann concluded that in comparison to breast and colorectal cancer survivors who make no changes in their physical activity levels from pre- to post-diagnosis, survivors who increase their physical activity levels by any amount experience a reduction in total mortality risk (RR = 0.61; 95 % CI = 0.46–0.80) [20].

Current recommendations for regular physical activity encourage all Americans to obtain 150 min weekly of moderate physical activity or 75 min of vigorous activity [3]. With respect to breast and colorectal cancer survivors, Schmid and Leitzmann found a decrease of 24 % in total mortality and a 28 % reduction, respectively, in those who exercised at least 150 min/week at a moderate intensity [19]. Hardee et al. similarly reported that resistance exercise was associated with a 33 % decreased risk for all-cause mortality in cancer survivors (95 % CI, 0.45–0.99) [1]. Although the precise mechanisms involved have not been clearly elucidated, the benefits are thought to be associated with reduced levels of circulating insulin and proinflammatory mediators as well as alterations in inflammatory pathways [20, 21].

Exercising during and after treatment appears safe and is associated with benefits such as improved physical functioning, exercise tolerance, body composition, cardiopulmonary fitness, and muscular strength, in addition to less fatigue, depression, and anxiety – factors that influence quality of life [3]. Weight resistance training during treatment has also been found to preserve lean body mass while decreasing the risk for gaining adipose tissue.

Despite the many benefits associated with physical activity, many cancer survivors remain sedentary [3]. A number of barriers may preclude survivors from obtaining regular physical activity, including: stage of disease, type of treatment undergoing or completed, and current health status. However, survivors who report regular physical activity patterns prior to diagnosis are more likely to continue exercising during and posttreatment. While beginning an exercise program during treatment may be difficult for some individuals, any exercise should be encouraged to obtain the reported benefits. Research shows that many cancer patients are willing to exercise through treatment, including the elderly. In fact, in a study by Sprod et al. on 408 elderly cancer patients (mean age of 73 and age range from 65 to 92), 46 % of the patients (65 years and older) reported exercising during treatment, as well as less shortness of breath and fatigue with improvements in overall general health and well-being during and after treatment [22].

Observational studies have indicated that one’s diet may affect cancer progression, risk of recurrence, and overall survival [3]. In addition, cancer survivors are at high risk for other chronic diseases including diabetes and heart disease. Therefore, dietary recommendations include adhering to the principles of a general, healthful diet put forth by the ACS and AICR, which includes adequate intake of macronutrients through consumption of fruits, vegetables, whole grains, and lean proteins [4, 27].

The foundation of a diet consists of carbohydrate, protein, and fat – all of which contribute energy (i.e., calories) within the diet. Overconsumption of these components not only can lead to increased risk of heart disease and diabetes but also to overweight and obesity. Overweight and obesity have also been shown to increase the risk of multiple comorbidities, including cancer [3]. Therefore, the goals of cancer survivors should include consumption of energy that is consistent with one’s energy usage. While various organizations have their own recommendations for diet composition for the adult, general intake recommendations are carbohydrate (45–65 % of calories), protein (10–35 % of calories), and fat (10–35 % of calories) [28].

Cancer can also cause a milieu of metabolic and physiologic effects that in turn can significantly alter the need for protein, carbohydrate, fat, vitamins, and minerals [3]. The ability to ingest adequate nutrition may be also be adversely affected due to disease and/or treatment-related side effects including anorexia, taste alterations, gastrointestinal changes, and other cancer and cancer treatment-related side effects. These, in turn, may lead to significant weight loss and poor nutritional status; therefore, during these instances, the goal is to prevent or reverse nutrient deficiencies and preserve lean body mass by treating and minimizing nutrition-related side effects. By identifying and treating nutrition-related impact symptoms, functional status and quality of life can also be improved (Table 13.3) [3].

The primary factor that has been shown to potentially influence one’s risk of cancer is overconsumption of energy. Obesity is due to the higher body adiposity that typically ensues when this occurs. This increased adiposity results in increased risk of ill effects on one’s health including production of reactive oxygen species, hyperinsulinemia, increased IGF-1 production, and increased estrogen production [29].

Breast cancer patients have been the primary focus of research on determining how diet and food choices affect progression and negative survival outcomes. More recently, however, there has been an increased focus on those afflicted with colorectal and prostate cancer and the effect that diet has on progression, recurrence risks, and survival.

Two large-scale, randomized controlled trials – the Women’s Intervention Nutrition Study (WINS) and the Women’s Healthy Eating and Living study (WHEL) – studied whether a diet lower in fat following the diagnosis of early-stage breast cancer can improve cancer outcomes [30]. The WINS study showed an inverse relationship between a low-fat diet (less than 15 % of calories from fat) and relapse-free survival with a 24 % decline in new breast cancer events [5]. Interestingly, an increased benefit was seen in only those women diagnosed with estrogen receptor-negative (ER-) disease. Conversely, the WHEL study did not find a statistically significant improvement in relapse-free survival despite a diet rich in vegetables, fruit, and fiber and, subsequently, lower in fat (aiming for 15–20 % of energy intake from fat). However, it was also found that women in this study failed to achieve these goals. It is important to note that women enrolled in the WINS study also experienced an average weight loss of 6 lb while those enrolled in the WHEL study did not lose a statistically significant amount of weight (less than 1 kg difference between control and intervention group); therefore, it is not known if the results of the WINS study were due to the weight lost or diet modification.