Why Food Is Medicine

Might Food Explain the Changes You Are Noticing in a Loved One?

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Scenario one: Does your (insert “son,” “daughter,” “wife,” “husband,” “partner,” etc.) seem down? Apathetic? Irritable? Socially isolated? You feel concerned about depression.

Scenario two: Does your (insert “son,” “daughter,” “wife,” “husband,” “partner,” etc.) seem irritable? You notice the moods swing high and low, wide and fast. You wonder if bipolar or some other diagnostic up-down mood label may be visiting your loved one.

Scenario three: You notice your (insert “son,” “daughter,” “wife,” “husband,” “partner,” etc.) seems newly or increasingly obsessed with food, food quality, food shows, recipe books, and cooking for others. You wonder if an eating disorder or an obsessive-type diagnosis might be appropriate labels for your loved one.

Responses to any of these scenarios are likely similar. As a caregiver or loved one, you might encourage your person to call for a psychiatric evaluation and a physical (or if you’re a parent, you may call for the person). Ruling out a biological cause of possible mental health complaints is generally recommended, so your loved one might visit a doctor to have an exam and labs run and to make sure that apparent mood or personality changes are not due to something better accounted for by a medical condition. A psychotropic medication evaluation with a psychiatrist may also be in the person’s best interest.

And, what about food? A culprit for what seems like a personality and/or mood change can sometimes come from food intake. We’ve all probably heard the expression, “You are what you eat.” Well, what about, “What is your person not eating?”

This article highlights ways that restricting food or dieting can affect a person both psychologically and physically and derives information from Ancel Keys’ study, the Minnesota Experiment (Franklin, Schiele, Brozek, & Keys, 1948).

This landmark 1940s experiment has helped people to understand the effects of semi-starvation, which can often resemble different psychiatric and even physical ailments.

The study included 36 men between the ages of 20 and 33. The active experiment lasted a total of approximately 1 year. The study featured a 3 month-control period followed by 6 months of a semi-starvation phase, meaning that participants’ daily energy intake was reduced from their regular intake during the control period (3,492 calories) to slightly less than half that (1,570 calories). Interestingly, the energy (AKA caloric) intake that resulted in these men experiencing semi-starvation can actually correspond with the energy intake of some of today’s popular diets. Finally, the participants returned to an increased caloric intake during a 3-month controlled rehabilitation period.

During the semi-starvation period—or what might even be seen nowadays as a normal “diet” period for some people—the researchers recorded various outcomes.

Notice how the following documented nutritional effects can look like psychological or physical ailments if you don’t know about the person’s food intake?

In the course of the study’s semi-starvation period, psychological and attitudinal changes such as “loss of ambition, narrowing of interests, depression, irritability, and loss of libido” (Franklin, Schiele, Brozek, & Keys, 1948, p. 30) occurred. Additional consequences included increased social isolation, increased senses of both inefficiency and ineffectiveness, and inability to concentrate. Sudden shifts between high and low mood periods were experienced. An overall attitude of apathy grew in the group of men.

Physically, these men were also affected by their semi-starvation in more ways than weight loss or an emerging appearance of emaciation. There were reports of slow nail growth and hair loss and regular complaints of muscle cramps and extremities seeming to fall asleep. Subjects regularly expressed feeling cold. Their bodies seemed to try and conserve energy (e.g., slowed pulse rates). Coordination typically became affected and physical movements slowed, except during some periods of seemingly random bursts of energy. By 3 months of reduced caloric intake, the study described that many experienced edema (e.g., swelling in the knees, ankles, and face). Interestingly, subjects’ reported physical sensations of hunger were experienced uniquely; descriptions spanned an array from reports of painful sensations in the abdominal area to tolerable discomfort. Loss of physical strength was commonly reported.

Notice how similar these symptoms can appear to reports of common physical or psychological ailments?

The Keys Study highlights that semi-starvation also seemed to result in an appearance of food-obsession. Conversations became food-focused. Pleasure seemed to be derived from watching people consume. Cookbooks and movie scenes with food images were noticeably attention-keepers. Some of the men reported dreaming of food.

Semi-starvation also seemed to affect attitudes and behaviors surrounding food. The subjects tended to become irritated around food service and preparation, often becoming possessive and defensive about their food. They began to consume odd concoctions of ingredients along with excessive spices and salt. Rituals around food increased, and the men appeared to try and stretch out consumption times, frequently engaging in ritualistic-type behaviors around food. Extra hot edibles and liquids became preferred; subjects seemed to demonstrate an increased tolerance to warm temperatures. Excessive gum chewing as well as coffee, tea, and water consumption seemed to be used as substitutes for food or fullness.

Notice how a combination of these symptoms could sound or look like an eating disorder or even other mental or medical issues? Focusing on the results of this experiment, it’s important to note that the subjects in this study were selected from the general public (and screened to be physically and psychologically healthy prior to the period of food restriction) and not specifically an eating disorder population.

If someone you love is presenting with any of the symptoms discussed in this article, and/or personality or attitudinal changes, that person may—or may not—be displaying signs of potential semi-starvation. The mental or medical health diagnostic label you might be considering may be true…and it might not be. Additionally, these types of symptoms may alert you that your loved one may—or may not—be struggling with disordered eating or an eating disorder. Eating disorders are known to have the highest mortality rates of any psychiatric illness, so if you believe your loved one might be affected by an eating disorder, please seek professional help and guidance as soon as possible.

This article does not encourage you to put nutritional considerations above or ahead of medical or mental health factors; initial health screenings and medication evaluations can both be vital to your physical and mental health. Either or both are often appropriate and necessary as frontline interventions. Rather, this article is meant to encourage you to also wonder about food intake if and when you notice changes in a loved one’s way of being. For example, you’re familiar with the colloquial expression “hangry,” right? It’s a great example that lack of food intake can greatly affect a loved one’s, or even your own, personality, mood, attitude, and behaviors. It’s important to note that nutrition seems to affect brain chemistry and overall mental health (Sarris et al., 2015). Here’s a historic and powerful reminder from the Father of Medicine, Hippocrates: “Let food be thy medicine and medicine be thy food.” In various situations, it will likely be beneficial for all people to include nutritional considerations along with attention given to potential medical and mental health concerns.

This article is not a substitute for professional medical or mental health advice. It is your responsibility to seek appropriate, professional help.


Franklin, J. C., Schiele, B. C., Brozek, J., & Keys, A. (1948). Observations on human behavior in experimental semistarvation and rehabilitation. Journal of Clinical Psychology, 4(1), 28-45

Sarris, J., Logan, A.C., Akbaraly, T. N., Amminger, G. P., Balanzá-Martínez, V., Freeman, M. P., . . . Jacka, F. N. (2015). Nutritional medicine as a mainstream in psychiatry. Lancet Psychiatry, 2(3), 271-274

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