Experts agree that a good diet should contain balanced amounts of food from five main food groups. These are:
Fruit and Vegetables
At least five portions of fruit and vegetables should be consumed every day. This isn’t as much as it sounds because this includes juices and snacks.
Starch
Starches include foods such as potatoes, rice, pasta, bread and other wholegrains.
Dairy Products
Dairy products include milk, cheese, and yogurt (assuming you have no dairy allergy).
Protein Foods
Protein is found in foods like meat, fish, eggs, beans, pulses and nuts (assuming you have no nut allergy).
Fat and Sugar
The current advice is that these should only be consumed in small quantities, although there is some controversy over whether a low-fat diet is really that good for you. (1)
What if I’m Vegetarian?
Vegetarians can still get fats and protein from eggs and other dairy products, beans, pulses (such as lentils), nuts and oils like olive oil so it is perfectly safe to exclude meat and fish from your diet.
Very strict vegetarians (vegans) who also exclude dairy products can maintain good health as long as they eat plenty of non-dairy protein sources (beans, pulses, nuts and oils).
As many strict vegetarians may be low in vitamin B12, found commonly in meat, they should also make sure they eat plenty of dried apricots, dates and figs as these all contain vitamin B12, as well as making sure they include broccoli and spinach in their vegetable selection and potatoes in their starch selection as these also contain vitamin B12.
The British Vegan Society recommends getting vitamin B12 from fortified breakfast cereals, milk substitute drinks, soy mince and yeast extract spreads as these are a good source of B vitamins (but only if you have no problems with yeast infections). (2)
The Low Fat Diet Controversy
A study carried out in the Cancer Research medical journal found that a low carbohydrate, high protein diet slows cancer growth in animals and that if animals were fed on a typical government recommended western diet (high carbohydrate, low fat) their cancer tumors spread more quickly.
Mice on a western diet developed cancer at a rate of nearly 50 percent, a rate similar to that of the one in three humans who are currently affected by cancer.
The researchers concluded:
"Taken together, our findings offer a compelling preclinical illustration of the ability of a low CHO diet in not only restricting weight gain but also cancer development and progression." (3)
The weight aspect is important because obesity rates are continuing to rise despite the recommendation for a low fat diet. In fact, there is limited evidence that a low fat diet keeps you slim.
The Nutrition medical journal wrote:
"Concerns that were raised with the first dietary recommendations 30 years ago have yet to be adequately addressed. The initial Dietary Goals for Americans (1977) proposed increases in carbohydrate intake and decreases in fat, saturated fat, cholesterol, and salt consumption that are carried further in the 2010 Dietary Guidelines Advisory Committee (DGAC) Report. Important aspects of these recommendations remain unproven, yet a dietary shift in this direction has already taken place even as overweight/obesity and diabetes have increased." (4)
The answer to the obesity and diabetes crisis may in fact be protein. Protein keeps you fuller for longer, so it suppresses hunger and the desire to snack on unhealthy fatty foods and may keep you slimmer as a result, so that egg sandwich for breakfast may not be as bad for you as you thought.
A study in the British Journal of Nutrition found that whey protein milkshakes produced a greater insulin response (important for preventing diabetes), reduced appetite and increased energy levels. They proposed that protein milkshakes would be a good choice of treatment for those with obesity. (5).
The Harvard School of Public Health say when choosing proteins for your diet, the key to good health is where you get your protein from. Since red meats can cause heart disease, this is not thought to be a good source of protein.
They recommend fish, poultry and beans as the best sources of protein with the least saturated fat. For instance, six ounces of salmon gives you 34 grams of protein and 18 grams of fat, four of them saturated, and a cup of cooked lentils give you 18 grams of protein but under one gram of fat.
Their overall recommendations are:
• Eat a variety of different foods.
• Have a low amount of saturated and trans fats but a higher amount of monounsaturated and polyunsaturated fats.
• Limit the amount of red meats you eat and don’t eat processed meats like sausage and beefburgers. If you eat red meat (like beef, pork or lamb) make sure you have no more than two 3-ounce servings a week.
• Eat soy in moderation (such as tofu).
• Balance carbohydrates and proteins. Cut back on highly processed carbohydrates (like white bread and white rice) and increase protein levels. (6 and 7)
Sources:
1. The Eatwell Plate, NHS Choices. Web. 31st May 2012. http://www.nhs.uk/Livewell/Goodfood/Pages/eatwell-plate.aspx
2. Sources of Vitamins, Net Doctor. Web. 31st May 2012. http://www.netdoctor.co.uk/focus/nutrition/facts/vitamins_minerals/vitamin.htm
3. A Low Carbohydrate, High Protein Diet Slows Tumor Growth and Prevents Cancer Initiation, Cancer Research, June 14, 2011; doi: 10.1158/0008-5472.CAN-10-3973.
Abstract: http://cancerres.aacrjournals.org/content/early/2011/06/10/0008-5472.CAN-10-3973.abstract
4. In the face of contradictory evidence: Report of the Dietary Guidelines for
Americans Committee, Nutrition 26 (2010) 915–924
http://www.spfldcol.edu/homepage/dept.nsf/91C8B01CAAC804C0852577C9006A5012/$File/Hite_Nutrition_2010.pdf
5. The acute effects of four protein meals on insulin, glucose, appetite and energy intake in lean men. Br J Nutr. 2010 Oct;104(8):1241-8. Epub 2010 May 11.
Abstract: http://www.ncbi.nlm.nih.gov/pubmed/20456814
6. The Nutrition Source, Protein. Harvard School of Public Health. Web. 31st May 2012.
http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/protein
7. The Nutrition Source, Fats and Cholesterol: Out with the Bad, in with the Good. Harvard School of Public Health. Web. 31st May 2012.
http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-full-story/index.html
Reviewed May 31, 2012
by Michele Blacksberg
Edited by Jody Smith