Decreased Appetite and Unintentional Weight Loss

What decreased appetite means

Appetite is the desire to eat. It is controlled by the brain (mainly the hypothalamus) in response to hormones from the gut and fat tissue, your blood sugar, your mood, smell and taste, and how quickly your stomach empties. When any part of that system is disturbed, appetite drops.

Doctors use the word anorexia for loss of appetite. This is not the same as anorexia nervosa, the eating disorder, in which hunger is usually present but food is deliberately restricted.

Decreased appetite can show up in several ways:

• not feeling hungry at usual mealtimes
• skipping meals without noticing
• early satiety: feeling full after a few bites
• food tasting or smelling unpleasant, or a metallic taste
• nausea at the thought of eating

Is decreased appetite normal?

Short dips are normal. Appetite naturally falls during infections, after a large meal, in hot weather, during short-term stress, and with age. Older adults often eat less because they move less, their sense of taste and smell weakens, and their stomach signals fullness sooner. What is not normal is a lasting change that causes weight loss, or appetite loss that comes with other new symptoms.

Decreased appetite and weight loss

Weight loss is the most useful measure of how serious appetite loss is, because it shows the body is short of energy over time. Doctors define unintentional weight loss as losing 5% or more of your body weight over 6 to 12 months without trying.

Clothes or rings feeling loose, a belt needing a new notch, or friends commenting that you look thinner are often the first signs. If you can, weigh yourself once a week at the same time of day and write it down. That record is very helpful to your doctor.

Common causes of decreased appetite

Short-term illness

• Viral infections such as colds, flu and COVID-19. Appetite usually returns as the fever settles.
• Stomach bugs (gastroenteritis): nausea, vomiting and diarrhea for 1 to 3 days, sometimes longer.
• Food poisoning, tonsillitis, urinary tract infections and other acute infections.

Mood and stress

• Depression: appetite loss with low mood, poor sleep, low energy and loss of pleasure that last more than 2 weeks. Some people eat more instead.
• Anxiety and stress: a "knotted" stomach, nausea and feeling too wound up to eat.
• Grief and major life changes.

Digestive problems

• Gastritis and peptic ulcers: burning upper belly pain, often worse or better with food, and nausea.
• Reflux (GERD): heartburn and regurgitation make eating uncomfortable.
• Constipation: a full, bloated feeling, very common in older adults and children.
• Celiac disease and inflammatory bowel disease: diarrhea, bloating, cramps and weight loss.
• Gastroparesis: delayed stomach emptying, often in diabetes, with early fullness and vomiting of undigested food.

Medicines and substances

Many medicines reduce appetite. Common ones include antibiotics, opioid painkillers, metformin, GLP-1 medicines used for diabetes and weight loss, some antidepressants, stimulants for ADHD, chemotherapy and digoxin. Alcohol, smoking, cannabis withdrawal and stimulant drugs such as cocaine or amphetamines also suppress hunger.

Pregnancy

Nausea and food aversions in the first trimester commonly reduce appetite. It usually improves by weeks 14 to 16.

Serious causes of decreased appetite and weight loss

These are less common, but they are why lasting appetite loss should be checked.

In older adults, the most common causes of unintentional weight loss are cancer, digestive diseases, depression and medicines. In up to about a quarter of people, no cause is found after a full assessment, and many of them do well on follow-up.

Symptoms that suggest a serious cause

• night sweats or fevers
• difficulty or pain swallowing
• persistent vomiting
• blood in the stool, black stools or vomiting blood
• a new lump anywhere
• a cough lasting more than 3 weeks, or coughing blood
• yellow skin or eyes
• severe tiredness or breathlessness

Decreased appetite in children and older adults

Children: toddlers' appetites vary a lot from day to day and growth slows after age 1, so they often eat less than parents expect. That is normal if they are active and growing along their curve. Worry if a child is losing weight, dropping across growth centiles, has ongoing diarrhea or tummy pain, or seems unwell or withdrawn. Teenagers who avoid food, are preoccupied with weight or exercise excessively should be assessed for an eating disorder such as anorexia nervosa.

Older adults: poor appetite is often caused by several things together: dental or denture problems, a dry mouth, medicines, constipation, loneliness, depression and difficulty shopping or cooking. Even modest weight loss increases the risk of falls, infections and frailty, so it deserves attention.

How doctors find the cause

Your doctor will ask:

• how long your appetite has been poor and how much weight you have lost
• what a typical day of eating looks like now
• about nausea, pain, bowel changes, swallowing, cough, sweats and fever
• about mood, stress, sleep, alcohol and drug use
• every medicine and supplement you take
• your smoking history and family history of cancer

They will weigh you and examine your mouth, neck, lymph nodes, chest, belly and skin. First tests usually include:

• full blood count, kidney and liver function, blood sugar (HbA1c), thyroid function, calcium and inflammation markers (CRP, ESR)
• urine test
• celiac antibody blood test
• a stool test for hidden blood (FIT) in some adults
• a chest X-ray, especially if you smoke or have a cough

If these give clues, or if weight loss continues, the next step may be an endoscopy, a CT scan of the chest and abdomen, or referral to a specialist.

How to manage decreased appetite

Treating the cause is what brings appetite back: settling an infection, adjusting a medicine, treating depression, or managing a thyroid or digestive problem. While that happens, these steps help you get enough energy and protein:

• Eat little and often. Aim for 5 to 6 small meals or snacks rather than 3 large meals.
• Make every bite count. Choose energy-dense foods: nut butters, eggs, cheese, yogurt, avocado, whole milk, olive oil drizzled on food.
• Drink between meals, not with them, so fluids do not fill you up.
• Use nourishing drinks such as milkshakes, smoothies or oral nutritional supplements if solid food is hard.
• Eat when your appetite is best. For many people that is breakfast.
• Light activity such as a short walk before meals can stimulate hunger.
• Make food appealing: small portions on a smaller plate, favorite foods, eating with others.
• Cold or bland foods smell less, which helps if nausea or smells put you off.

Appetite stimulant medicines are sometimes prescribed for specific situations such as cancer or HIV-related weight loss, but they are used only under a doctor's supervision and do not replace finding the cause. A registered dietitian can help if weight keeps falling.

Frequently asked questions

What does decreased appetite mean?

It means you have less desire to eat than usual. You may skip meals, eat smaller portions or feel full quickly. It is a symptom rather than a diagnosis, and it can come from minor problems such as a cold or stress, or from longer-term conditions such as depression, thyroid disease or, less often, cancer.

Is decreased appetite normal?

Short dips are normal during an infection, a stressful week or very hot weather, and appetite naturally falls a little with age. It is not normal if it lasts more than 2 to 3 weeks, causes weight loss, or comes with other new symptoms such as pain, vomiting, fever or night sweats.

When is decreased appetite and weight loss a concern?

See a doctor if you lose 5% or more of your body weight over 6 to 12 months without trying, or if weight is dropping quickly. Get help sooner if weight loss comes with swallowing problems, persistent vomiting, blood in your stool, night sweats, a lump or a persistent cough.

Can anxiety cause loss of appetite?

Yes. Stress hormones slow digestion and can cause nausea and a tight stomach, so many people do not feel hungry when anxious. It usually returns when the stress eases. If anxiety and poor appetite last for weeks, treatment such as talking therapy can help both.

What are the symptoms that come with decreased appetite?

Common companions are tiredness, nausea, feeling full quickly, bloating and weight loss. The other symptoms point to the cause: fever suggests infection, low mood suggests depression, heartburn suggests gastritis or reflux, and night sweats or a lump need prompt medical review.

What can I eat when I have no appetite?

Choose small portions of energy-dense, easy foods: yogurt, eggs, cheese and crackers, nut butter on toast, soup, smoothies or milkshakes. Eat every 2 to 3 hours rather than waiting to feel hungry, and keep drinks for between meals so they do not fill you up.