Body Weight Loss: Carb or Calorie Restriction
Transitioning my Macronutrients via Fat Loss Bible
Long story short, I’ve gone from eating a low carb diet patterned after Sisson’s Carbohydrate Curve in the “Primal Blueprint” to a diet with enough carbs to adequately fuel endurance activities and provide nutrients for proper recovery as outlined in Colpo’s “Fat Loss Bible”. This is a point of distinction: Sisson advocates carb restriction, Colpo advocates calorie restriction.
Sisson acknowledges in his book that the chronic cardio crowd (his description) needs to eat more carbs than his recommended carbohydrate curve, but he also recommends against this lifestyle citing eventual weight gain from eating more than 150 grams of carbs daily (pg. 89, 92 in PB). In contrast Colpo recommends carbs as “jet fuel” (chapter 15) for endurance activities. He promotes the combination of exercise (both endurance and resistance) and calorie restriction (or deficit) as the recipe for fat loss.
I’ve experienced both diets during periods of running and non-running. I’ve lost similar amounts of weight on both diets, and the weight loss was proportional to my approximate activity level (running accelerated the weight loss for both diets). On average, the total calorie levels were a little lower for the low carb diet which I will address below. Given similar weight loss no matter the diet, I’m no longer carbophobic, as I experienced weight loss in the region of 250-300 grams of daily carbs, which is well into Sisson's warning and danger zone on his carbohydrate curve.
In fact I’m carbophilic as I’ve experienced more energy for performance during hard interval running sessions. My one regret during these experiments is that I did not track my body fat content until recent months, so I can’t say whether body weight loss on both diets was due to fat, muscle or some combination. In the last 12 weeks my body fat content dropped from about 20% to 16%. If you want to know the nitty gritty of my experiences, then please read on.
It was the last week of August when I decided to make a change in my diet. My previous diet was a ketogenic diet, or one targeting under 75 grams daily carbohydrates ala Mark Sisson's "Primal Blueprint". The targeted daily grams of fat and protein were around 130-150 grams each. The calories from this diet consisted of less than 15% carbohydrates and more than 50% fat, and the remainder is protein. It looked like this:
For the next twelve weeks my diet targets changed based on these calculations to 200-250 grams carbohydrates, about 144 grams proteins and 47-69 grams fat. To reduce the fat, there were three staples from my ketogenic diet that had to be cut: nuts, cheese and heavy whipping cream. A typical daily menu looked like:
- breakfast: 2-3 hard boiled eggs
- lunch: 2 bananas, 2 apples, carrots, grapes
- dinner: meat, potatoes, veggies
The average daily calories and average daily grams of carbs for each week are plotted in the chart below.
Weeks 1-3 could best be described as a transition ramping up the carbs. It was difficult to figure out what and how much to eat since the proportion of the macronutrients changed so much. Week 1 resulted in eating too few calories and losing a few pounds. In week 2 and 3 I gained 4 pounds even though my total calories were relatively low and I was running moderately. I think this initial weight gain can be attributed to restoring glycogen and hydration levels in my muscles after eating a ketogenic diet for months. For someone who weighs 75 kilogram (close to my weight) there are about 450 grams (about 1 pound) of glycogen in the muscles (chapter 15, FLB). Each gram of glycogen is bound with 3-4 grams of water (chapter 1, FLB). So gaining about 1 pound of glycogen would be accompanied with a gain of about 3-4 pounds of water.
In weeks 4-7 I lost 7 pounds while eating 240-280 grams carbs daily. My activity level was still moderate, running about 25-35 miles per week including a few interval sessions per week. I ate more calories than I intended to as I found it difficult to restrict calories while running.
In weeks 8-12 all running stopped from the return of an old groin injury. I did about 30 minutes per day of core exercises for rehabilitation. Weight loss continued as I dropped total calories by about 15-20%. I lost 5 pounds.
The point of my experiment was to measure weight loss from a low carb diet compared to an isocaloric diet with enough carbs. The comparisons of both diets while running and non-running is shown in the table below:
- during periods of non-running (minimal exercise), I lost 1 pound per week on both diets (14% vs. 50% carbs).
- during periods of running (moderate exercise), I lost about 2 pounds per week on both diets (11% vs. 45% carbs). However, the diets were not precisely isocaloric. The higher carb diet had about 20% more calories and weight loss was about 10% less. I think the extra calories were partially offset by better running performance.
So what's the next step? Logan wants to get P90X. Apparently, he's experiencing the "freshman 15", although you couldn't tell from the pic below. I'm sticking to the same eating plan, intending to drop more pounds. I'm looking forward to dropping some time from races as well, if or when I get back to running. My groin injury is better, but it seems like a long road to recovery. If things go well, I'll sign up for a spring half and full marathon.
|Me and Logan - November 2011|