Eating walnuts may help control appetite: Study

Individuals who regularly consume walnuts, salmon and canola oil — rich in polyunsaturated fats (PUFAs) — are likely to experience hormonal changes that can control appetite and make them feel less hungry, a study has shown.

The study found that consuming a diet high in PUFAs caused a significant decrease in fasting ghrelin — a hormone that increases hunger.

Further, a PUFA rich diet also caused significant increase in peptide YY (PYY) — a hormone that increases fullness or satiety.

“Appetite hormones play an important role in regulating how much we eat,” said lead researcher Jamie A. Cooper, from the University of Georgia.

“These findings tell us that eating foods rich in PUFAs, like those found in walnuts, may favourably change appetite hormones so that we can feel fuller for longer,” Cooper added.

For the study, detailed in the journal Nutrition, the team enrolled 26 healthy men and women (ages 18-35) who were placed on a seven-day diet high in PUFAs or a control diet consisting of a typical American eating pattern.

The PUFA-rich diet included whole foods such as walnuts, Alaska salmon, tuna, flaxseed oil, grape-seed oil, canola oil, and fish oil supplements. All meals were provided by the researchers.

The control diet was comprised of 7 per cent polyunsaturated fat, 15 per cent monounsaturated fat and 13 per cent saturated fat, compared to the PUFA-rich diet which was 21 per cent polyunsaturated fat, 9 per cent monounsaturated fat, and 5 per cent saturated fat.

The participants experienced increases in PYY while fasting and after consuming a meal. These types of hormone changes imply better appetite control, the researchers said.

Diet Diary: Why all that you read about red meat may not be right

Beef: Round, Sirloin, Shuck, Loin
Veal: All trimmed cuts
Pork: Tenderloin, leg (fresh), shoulder (arm or picnic)
Lamb: Leg, arm, loin

Red meat has acquired a negative reputation. Messages about its consumption are both confusing and misleading. It is generally believed that meat is rich in fat and cholesterol and a high intake of it, is associated with heart disease, diabetes and cancer. In fact, the fat and cholesterol content in lean red meat are comparable to poultry and fish.

A paper which reviewed 54 studies on the relation between red meat consumption and coronary artery disease, reveals that red meat may not be as bad as it is believed to be. Substantial evidence from recent studies show that lean red meat trimmed of visible fat does not raise blood cholesterol and LDL (bad) cholesterol levels.

Intake of harmful fats mainly comes from hydrogenated fats in fast foods, snacks, oils, spreads and other processed foods and visible fat of meat — referred to as charbi in Hindi — rather than from lean red meat. In fact, lean red meat is low in saturated fat and if consumed as a part of a healthy diet, is associated with reductions in LDL(bad) cholesterol in individuals with high and normal cholesterol levels. Lean red meat consumption has been found to have no effect on clotting properties of blood by researchers.

From an evolutionary perspective, human diet histories show that for a period of at least 2 million years, our ancestors consumed increasing quantities of meat. This meat was wild game — low in total and saturated fat and relatively high in poly-unsaturated fats (PUFA). The evidence presented in these reviews indicates that meat was a major energy source in pre-agricultural humans.

red meat, red meat consumption, red meat effects, cholesterol levels in red meat, red meat diseases, health newsOn the basis of several reviews, scientific evidence is accumulating that lean red meat is a healthy and beneficial component of any well balanced diet as long as it is fat trimmed and consumed as a part of a varied diet. It emphasises that meat itself is not a risk factor for western lifestyle diseases such as cardiovascular disease, heart disease, diabetes and cancer, but, rather the risk stems from excessive consumption of harmful hydrogenated fats and untrimmed fatty meat of modern grain and concentrate fed domesticated animals.

Although there are some conflicting studies which associate red meat consumption with increased inflammation and increased risk of metabolic syndrome, diabetes and heart disease, the important thing to remember is that they do not take into account the quality of meat and several have been done on processed and cured meats like sausages, bacon, salami etc.

Meat is a good source of protein, omega-3 fatty acids, vitamin B12, niacin, zinc and bio-available heme iron, a form of iron which is far more readily absorbed compared to iron found in plant foods. For women and teenage girls, who are more likely to get iron deficiency anaemia, lean red meat may be an important source of iron.

As is well known, ‘the dose makes the poison’. People who experience increased risk of colon cancer are those who consume more than 250 gms of red meat everyday.

Along with the quantity, the quality of meat and its processing also counts. Scientific evidence reveals that processed meat like sausages, bacon and salami increase the risk of bowel cancer more than red meat. They are not only high on fats but also contain potentially carcinogenic components such as nitrites. It is recommended that cured or processed meats be eaten as a condiment or flavouring with foods rather than as a main dish. Therefore, the American Cancer Society advocates limited intake of processed meats. Organ meats such as liver and kidney are relatively low in fat but high in cholesterol, and should be eaten less often, no more than once a month.

Other issues which need to be addressed are cooking methods — how healthy your diet is and how much of vegetables and fruits you eat. Cooking meats at very high temperatures such as frying or barbecuing, eating too much of char-grilled meat and processed meat is undesirable as it forms harmful compounds which can be carcinogenic. Cook meat in healthy ways — bake, roast or broil and do not fry. Marinating with herbs such as ginger, garlic and turmeric reduces formation of harmful compounds.