|
LOSING WEIGHT SAFELY
Many people try to lose weight. To do this they must reduce their CALORIES intake. It is important to do this SAFELY and STEADILY. Regular EXERCISE is an important contributor to safe weight loss. Starvation or semi-starvation or reducing weight very quickly is dangerous. Sometimes it is suggested that we just eat “less of everything”.This is likely to result in a serious lack of PROTEIN, VITAMINS, MINERALS & other VALUABLE PROTECTIVE SUBSTANCES.
WHAT SHOULD WE EAT?
To calculate every day the RECOMMENDED DAILY AMOUNT (RDA) of vitamins & minerals in all our food would require skilful weighing and a computer. (The software exists, but not all of us can manage to live our lives making these complicated calculations). We can however adopt some sensible choices to maximise nutritional value.
HIGH NUTRITION
We must get enough PROTEIN. Requirements vary but a reasonably safe daily minimum is probably around 60g (grams) from all sources. There is some evidence that for maximum nutrition, we should aim higher. Even a little fish or very lean meat will seriously raise daily protein intake. These need not add many calories if they come without fat, oil or ‘batter’. An increase in intake of green vegetables brings large benefits with few calories. The Table below shows how much protein there is in just 100Kcal worth of spinach, broccoli & kale. In addition to protein, these vegetables bring other important nutrients. Soy protein sources are useful in a similar way. A recent thoroughgoing science study (quoted below**) of long term calorie restriction showed astonishingly reduced risk factors for arterial heart disease. Changes in food choices were necessary in order to achieve high nutrition with fewer calories. People’s choices in this study brought them closer to 100g protein per day. Perhaps 70g protein or over could be a useful target for us lesser mortals.
In the same study, certain FATS were avoided or reduced. ‘Trans-fat’, even in small quantities, was totally avoided, which meant no manufactured spreads. Saturated fat was kept to a minimum, which meant careful choice of meat and animal products – see the Table below for examples. Monounsaturated fat was from many sources, including nuts, almonds, walnuts and hazel. Total fat per day from all sources averaged about 50 - 60g fat/oil. Having a reasonably high intake of monounsaturated fat at the same time as seriously reducing the daily total of calories probably accounted for the very healthy high levels of (“good”) HDL recorded in cholesterol tests (quoted below**). Almonds are high in monounsaturated fat (1oz, 24 nuts, contains 9g).
MINERALS & VITAMINS are usually best obtained from vegetable sources, although Vitamin B12 can be obtained only from animal sources. A small fillet of haddock (3½oz, 100g) will supply 60% RDA of B12 as well as 25% niacin and13% magnesium, for fewer than 100Kcal. Magnesium, folic acid and Vitamins B6 & B12 are particularly important for arterial / heart disease. Diets should not be salty. (See also Table below.) When you are losing weight, taking a multivitamin and minerals tablet that provides 100% RDA of essential vitamins is a reasonable “insurance” policy. Kale (100g) can provide female RDA percentages of 200% Vitamin C, 38% Vitamin A (as beta-carotene), 31% magnesium, 25% calcium, 20% iron, 15% folic acid, 14% B6. Spinach (100g) contains female RDA percentages of 100% Vitamin A, 81% folic acid, 31% magnesium, 24% iron, 18% riboflavin, 17% calcium, 16% Vitamin C, 15% B6. Less than 2oz (50g dry weight) of a legume like lentils will provide when cooked more than 100% RDA folic acid, 30% of iron, 19% magnesium, 15% zinc, 14% thiamine and 11% B6, and a banana more than a third of B6 RDA. Carrot is a rich source of 2 kinds of beta-carotene (precursor for Vitamin A). A quarter cup (1oz) of Wheatgerm, as well as 106Kcal, provides female RDA percentages of 50% thiamine, 46% folic acid, 30% zinc, 25% magnesium, 24% B6, 13% niacin, 11% riboflavin. Two Brazil nuts will supply sufficient selenium. PROTECTIVE NUTRIENTS are found in most fruits and vegetables (even in the humble lettuce, carrot, apple, orange, & onion). What is protective for arteries and the heart is usually preventive against cancer. Fruits do not provide much protein for the calories they contain, but nevertheless are very valuable. The berries, and blackcurrants as well as vegetables broccoli, kale, onion, and turmeric spice, and tomato paste with a little oil deserve special mention. Extra-virgin olive oil is useful in cooking and dressings and seems to contain protective substances. Green tea (and to a lesser extent ordinary black tea) seems especially valuable. Cocoa powder without sugar makes a good occasional drink. (The saturated fat in cocoa seems less of a problem. Chocolate contains milk fat as well as sugar in addition to cocoa).
PROTEIN FOR CALORIES
Table
NA = data “not available”. RDA figures are from official USA data. Note that ‘RDA’ for magnesium is higher for men than for women; a middle figure is quoted for the purpose only of making approximate comparison between foods.
|
PROTEIN, calcium & magnesium per 100 KILOCALORIES (“calories”)
|
|
Selected foods (quantities provide 100Kcal)
|
PROTEIN grams per 100 Kcal
|
Calcium % RDA per 100 Kcal
|
Magnesium % RDA per 100 Kcal
|
|
Haddock (raw 4oz / 115g) 1
|
21.7
|
4%
|
12%
|
|
*Egg white (6 egg whites =100Kcal)
|
21.0
|
negligible
|
8%
|
|
Chicken white meat roasted, (1.8oz) 1, 3
|
17.9
|
negligible
|
45%
|
|
Beef very lean grilled, (1.7oz, half the raw weight)1, 3
|
17.0
|
negligible
|
6%
|
|
Soy flour low-fat <8g/100g (1oz or 28g )
|
13.5
|
7%
|
23%
|
|
Spinach (cooked 434g )
|
12.9
|
74%
|
120%
|
|
Broccoli (raw 325g or 2 full spears )
|
10.6
|
21%
|
32%
|
|
Skim milk (250 ml,) 1
|
9.7
|
43%
|
14%
|
|
Lentils uncooked dry (1oz or 29g)
|
8.2
|
negligible
|
10%
|
|
Soy flour wholemeal (¾ oz or 22g)
|
8.1
|
6%
|
30%
|
|
Soya drink (220ml ‘Sojasun Calcio’ organic)
|
8.0
|
33%
|
NA
|
|
Haricot beans (1¼ oz or 37g)
|
7.9
|
6%
|
18%
|
|
Split peas (cooked, drained, 3oz or 85g)
|
7.0
|
negligible
|
11%
|
|
Oatbran (approx. 1½ oz or 41g) *
|
7.0
|
3%
|
30%
|
|
Kale (raw, 8½oz or 240g)
|
6.6
|
61%
|
75%
|
|
Wheatgerm (1oz or ¼ cup or 29g)
|
6.4
|
negligible
|
21%
|
|
Pease pudding (‘Foresight’ cooked, ½ can or 106g) 2
|
6.4
|
NA
|
NA
|
|
Bread (‘Hovis’ wholemeal, approx. 1 slice) 2
|
5.1
|
NA
|
NA
|
|
Oats (flakes, meal, approx. 1oz or 26g)
|
3.4
|
negligible
|
14%
|
|
Almonds (17-18 nuts)
|
3.4
|
6%
|
16%
|
|
*Earlier versions of this table (before November 2005) had a lower & incorrect figure for the oatbran protein per 100Kcal.
1 contains cholesterol
2 contains significant salt
3 contains more than 1g saturated fat per 100Kcal
* egg white is not a rich source of Vitamin B12.
** The most detailed scientific study to date of safely losing weight (reported by Fontana L. et al. in PNAS, April 27, 2004,vol. 101, 17, 6659–6663) is most encouraging. Though few of us could achieve such a stringently controlled low weight, we can learn from the study. Risk factors for arterial and heart disease were dramatically improved. Blood pressure dropped to that typical of 10 year olds. Blood sugar was astonishingly well controlled. “Bad” cholesterol in the blood was much reduced while “good” cholesterol was increased (to 1.5mmol/L at 12 months and 1.7mmol/L subsequently). In other blood tests, a key indicator of inflammation, C-reactive protein, CRP, was extremely low by normal standards.
Quote from 2004 study of CR (Calorie Restriction with high nutrition) The CR subjects designed their diets to consume a balance of foods that supply more than 100% of the Recommended Daily Intake (RDI) for all of the essential nutrients, while minimising energy content (1,112–1,958 kcal/day). They eat a wide variety of vegetables, fruits, nuts, dairy products, egg whites, wheat and soy proteins, and meat (approx.26% of calories from protein, approx.28% from fat, and approx. 46% from complex carbohydrates). All of CR group strictly avoids processed foods containing trans fatty acids and high glycemic foods (e.g., refined carbohydrates, desserts, snacks, and soft drinks). The comparison group ate typical U.S. diets containing nearly twice as many calories as the CR subjects (1,976–3,537 kcal/day; approx.18% calories from protein, approx.32% from fat, and approx.50% from carbohydrates).
|
