So lets get started..........
ACCEPTABLE IN THE 80'S NO 2 - HIGH CARB, LOW FAT DIETS
The thinking in the 80's was that if we didn't eat fat we wouldn't be fat, sounds sensible.
Well Walter Willett, Chair of the department of nutrtion at Harvard School of Health, had this to say:
"The idea that all fat is bad for you, the exclusive focus on adverse effects of fat, may have contributed to the obesity epidemic.... The emphasis on total fat reduction has been a serious distraction in the efforts to control obesity and improve health in general."
The Different types of fat
There are 4 different types of fat - Monounsaturated, Polyunsaturated, Saturated and tran's fat which can be further broke down into good and bad fats.
Monounsaturated fats (good fats)
Monounsaturated fats are said to help reduce cholesterol, blood pressure and help with the control of diabetes.
Polyunsaturated fats (good fats)
Polyunsaturated fats help to improve immune function and help to protect against sudden death from heart disease.
Polyunsaturated fats can be broken down into 2 catagories:- omega 3 and omega 6.
Saturated fats (bad fats)
Saturated fats raise the risk of heart disease and stroke, as well as cholestrol. In fact they are twice as potent at raising cholestrol as polyunsaturated fats are at lowering cholestrol levels.
Tran's fats (bad fats)
Trans fats increase the risk of heart disease and stroke.
Omega 3 fish oil and fat loss
One of the reasons why we where told not to eat fat in the 80's was that there was little human data available about fish oil and fat loss until the late 1990's.
- One of the earliest studies on fish oil and fat loss in humans was published in 1997 in the International Journal of Obesity (Couet 1997). The purpose of the study was to investigate the effect of substituting fish oil for other visible dietary fats on body fat mass and substrate oxidation in healthy adult humans.
Six male subjects were fed a control diet ad libitum (as much food as they wanted) for 3 weeks. 12 weeks later, they were given a diet with the same amount of calories, only this time with 6 grams per day of fish oil replacing 6 grams of other dietary fat. During both periods, the researchers measured energy intake, resting metabolic rate, basal substrate oxidation and body fat (using dual x ray absorpitometry, a sophisticated and highly accurate way to measure body fat composition).
The fish oil was given to the experimental group as 8 capsules of 750mg (2 at breakfast, 3 at lunch, and 3 at dinner). This amounted to 1.1 grams of DHA and 0.7 grams of EPA, for a total of 1.8 grams of long chain omega 3 fatty acids per day.
Food intake was carefully controlled, with all meals deing ingested in the metabolic laboratory. Food was weighed and cooked by a dietician before being served, and leftover food was weighed and accounted for in the calculation of calorie intake.
The subjects body weight did not change, but there body composition did: the fish oil group lost 2 pounds of fat compared to 0.7 pounds of fat in the group without fish oil. The researchers noted however, that these differences did not reach statistical significance.
There was also a difference in resting metabolic rate: The resting metabolic rate of the fish oil group was 1775 kcal per day, compared to 1710 kcal per day for the no fish oil group.
Of most significance, the rate of fat oxidation in the fish oil group increased by 25% over the group that did not take fish oil.
- 2006, Czech researchers (kunesova, et al) from Charles University's obesity management centre in Prague. Took 20 severely obese women who were randomly assigned to either a very low calorie diet and placebo or a very low calorie diet with an omega 3 (EPA and DHA) supplement. The subjects also performed about 60 minutes daily of light physical activity.
- A study published in the International Journal of Obesity (Garulet 2006) showed for the first time in humans that omega-3 and omega-6 fatty acids were related to reduce fat cell size in certain lacations on the body. The same study showed that in contrast, saturated dietary fatty acids significantly correlated with an increase in fat cell size and number.
Low carb diets and fat loss
As you can see not all fats are bad for you, and some fats can even help with fat loss. But there was another side to the nutritional strategy of the 80's it was high carbohydrate intake. This is probably the worst part of the 80's nutritional strategies, because of are own recommendations (6-11 servings of refined carbs in the food pyramid) we created Type 2 diabetes.
- A study comparing different diets (Atkins, Zone, Learn and Ornish) was published in the Journal of the American Medical Association Vol 297 No.9 pp 969-977)
The study was entitled the A TO Z Weight Loss Study (Atkins, Traditional, Ornish, Zone)
Briefly:
311 people were randomly assigned to a diet for 12 months.
Results after 12 months:
Atkins Diet: -4.7kg (10.4lbs)
Zone Diet: -1.6kg (3.5lbs)
Learn Diet (traditional diet recommendations -- low fat high carbs) : -2.6kg (5.7lbs)
Ornish Diet: -2.2kg (4.8lbs)
The diet essentially looked at different gradations of carbohydrate intake on weight loss.
Basically -- the Atkins diet (low carb, high fat, high protein diet) outperformed the other diets VERY significantly in terms of fat loss. There was no statistically significant difference in fat loss between the other groups.
Important to note is that total energy intake was NOT different among the diet groups at the baseline measure or any subsequent point -- they all ate the same total calories. However, over time all four groups significantly decreased caloric intake over the course of the study - they all did eat less to generate fat loss - but they all ate the same amount.
Pilot 12-Week Feeding Weight-Loss Comparison: Low-Fat vs Low-Carbohydrate (Ketogenic) Diets," Abstract Presented at The North American Association for the Study of Obesity Annual Meeting 2003, Obesity Research, 11S, 2003, page 95OR.
- Greene, P., Willett, W., Devecis, J., et al.,
Three groups on different diets for 12 weeks:
Low fat/low cal (1800 cals per day) diet: Lost on average 17 lbs
Low carb/higher cal (+300) group: Lost on average 20 lbs.
- Meckling KA, Sherfey R
A randomized trial of a hypocaloric high-protein diet, with and without exercise, on weight loss, fitness, and markers of the Metabolic Syndrome in overweight and obese women.
Appl Physiol Nutr Metab. 2007 Aug;32(4):743-752.
The subjects were divided into two main groups - high carb (3:1 carb:protein) and low carb (1:1 carb: protein) and then subdivided into exercise (three times per week) and non exercise groups within each diet group.
Weight loss after 12 weeks was as follows:
4.6lbs for high carb no exercise group
8.8lbs for high carb with exercise group
10.1lbs for the high protein-low carb -no exercise group
and 15.5 lbs for the high protein, low carb with exercise group.
What's really interesting is that the high protein, low carb group was superior for weight loss over high carb with exercise. And it was 75% superior when combined with exercise.
In conclusion
I hope over the 2 articles that i have given you some ideas on more effective approaches to fat loss training and eating. Lower your refined carb intake and up your good fat intake. Start with a good resistance training program then add interval type training sessions. Follow these ideas and you will be on the road to fat loss success.
PS. I would like to thank my mentor Alwyn Cosgrove and Tom Venuto for bringing these research studies to light for fitness professionals all over the world.
PPS. As a tribute to Calvin Harris and the song Acceptable in the 80's that started the idea of the article in my head, please watch the video below
