Carbs And Protein For Muscle Recovery

A paper from several years ago supports the traditional wisdom for post-workout muscle recover, abstract:

The objective of the study was to investigate whether co-ingestion of carbohydrate and protein as compared with protein alone augments muscle protein synthesis (MPS) during early exercise recovery. Two months old rats performed 10 repetitions of ladder climbing with 75% of body weight attached to their tails. Placebo (PLA), whey protein (WP), or whey protein plus carbohydrate (CP) was then given to rats by gavage. An additional group of sedentary rats (SED) was used as controls. Blood samples were collected immediately and at either 1 or 2 h after exercise. The flexor hallucis longus muscle was excised at 1 or 2 h post exercise for analysis of MPS and related signaling proteins. MPS was significantly increased by CP compared with PLA (p<0.05), and approached significance compared with WP at 1 h post exercise (p = 0.08). CP yielded a greater phosphorylation of mTOR compared with SED and PLA at 1 h post exercise and SED and WP at 2 h post exercise. CP also increased phosphorylation of p70S6K compared with SED at 1 and 2 h post exercise. 4E-BP1 phosphorylation was inhibited by PLA at 1 h but elevated by WP and CP at 2 h post exercise relative to SED. The phosphorylation of AMPK was elevated by exercise at 1 h post exercise, and this elevated level was sustained only in the WP group at 2 h. The phosphorylation of Akt, GSK3, and eIF2Bε were unchanged by treatments. Plasma insulin was transiently increased by CP at 1 h post exercise. In conclusion, post-exercise CP supplementation increases MPS post exercise relative to PLA and possibly WP, which may have been mediated by greater activation of the mTOR signaling pathway

Carbs and protein post-resistance training therefore proved here superior to protein alone.

Low Carb Ironman Training?

One possible way to overcome carbohydrate (carb) storage limitations for extreme duration athletic events like Ironman triathlons is for the athlete to train under a low-carb diet, to get the body acclimated to that condition, and then giving carb supplementation during the completion, providing the levels that the now-adjusted body can utilize.  Keep in mind that another study, looking at elite race walkers (somewhat less extreme that the Ironman) found that low carb diets were negative for performance.  So the current finding (abstract below) may apply only to the most extreme events where “carb loading is inefficient?  More study is required.

Ironman triathlons are ultra-endurance events of extreme duration. The performance level of those competing varies dramatically, with elite competitors finishing in ~ 8:00:00, and lower performing amateurs finishing in ~ 14-15:00:00. When applying appropriate values for swimming, cycling and running economies to these performance times, it is demonstrated that the absolute energy cost of these events is high, and the rate of energy expenditure increases in proportion with the athlete's competitive level. Given the finite human capacity for endogenous carbohydrate storage, minimising the endogenous carbohydrate cost associated with performing exercise at competitive intensities should be a goal of Ironman preparation. A range of strategies exist that may help to achieve this goal, including, but not limited to, adoption of a low-carbohydrate diet, exogenous carbohydrate supplementation and periodised training with low carbohydrate availability. Given the diverse metabolic stimuli evoked by Ironman triathlons at different performance levels, it is proposed that the performance level of the Ironman triathlete is considered when adopting metabolic strategies to minimise the endogenous carbohydrate cost associated with exercise at competitive intensities. Specifically, periodised training with low carbohydrate availability combined with exogenous carbohydrate supplementation during competition might be most appropriate for elite and top-amateur Ironman triathletes who elicit very high rates of energy expenditure. Conversely, the adoption of a low-carbohydrate or ketogenic diet might be appropriate for some lower performance amateurs (> 12 h), in whom associated high rates of fat oxidation may be almost completely sufficient to match the energy demands required.

Fad Diets Not Necessary

More support for the ides that “fad” diets – like low carb – are not necessary for weight control and dealing with metabolic syndrome. Take home point: “any diet type resulting in reduced energy intake will result in weight loss and related favorable metabolic and functional changes.”  Abstract:

In the past, different types of diet with a generally low-carbohydrate content (< 50-< 20 g/day) have been promoted, for weight loss and diabetes, and the effectiveness of a very low dietary carbohydrate content has always been a matter of debate. A significant reduction in the amount of carbohydrates in the diet is usually accompanied by an increase in the amount of fat and to a lesser extent, also protein. Accordingly, using the term "low carb-high fat" (LCHF) diet is most appropriate. Low/very low intakes of carbohydrate food sources may impact on overall diet quality and long-term effects of such drastic diet changes remain at present unknown. This narrative review highlights recent metabolic and clinical outcomes of studies as well as practical feasibility of low LCHF diets. A few relevant observations are as follows: (1) any diet type resulting in reduced energy intake will result in weight loss and related favorable metabolic and functional changes; (2) short-term LCHF studies show both favorable and less desirable effects; (3) sustained adherence to a ketogenic LCHF diet appears to be difficult. A non-ketogenic diet supplying 100-150 g carbohydrate/day, under good control, may be more practical. (4) There is lack of data supporting long-term efficacy, safety and health benefits of LCHF diets. Any recommendation should be judged in this light. (5) Lifestyle intervention in people at high risk of developing type 2 diabetes, while maintaining a relative carbohydrate-rich diet, results in long-term prevention of progression to type 2 diabetes and is generally seen as safe.

Carbs and Cancer: Glycaemic Index and Lung Cancer

Is eating certain carbs as bad as smoking?

PITTSBURGH (KDKA) – You’ve heard that carbs can increase your waistline, but according to a new study they could be as bad for you as smoking cigarettes.
 

The study found carbs can actually raise the risk of lung cancer by some 49-percent.
 
Scientists found foods with a high glycaemic index, such as white bread, may increase the risks of cancer.
 
The report says glycaemic index is a measure of the quality of dietary carbohydrates – and is defined by how certain foods affect our blood sugar levels after eating.
 
The theory behind the study is that high-GI foods trigger higher levels of glucose and insulin in the blood, which in turn increase Insulin-Like Growth Factors (IGFs).
 
The study was conducted by the University of Texas MD Anderson Cancer Center.
 
Lead author on the study, Dr. Stephanie Melkonian says: “We observed a 49 percent increased risk of lung cancer among subjects with the highest daily GI compared to those with the lowest daily GI.”
 
The study says people should limit their intake of foods and beverages with a high GI.

So, in this study is was not total carbs per se that was the problem, but rather, the type of carbs - in other words a qualitative rather than strictly quantitative problem. Therefore, "white" and "starchy" carbs are a problem, by causing blood glucose spikes that result in higher levels of insulin and insulin-like growth factors. Whole wheat, etc, as much as non-starchy vegetables and many fruits, do not have the same effect. Although the problem is qualitative in that the type of carbs is what's most important, of course how much you eat of it will influence risk. Eating some occasional white bread and rice (which I for one try to avoid as much as possible) is likely not going to be as risky as stuffing your face with it every day, especially multiple times per day. Eating some potatoes won't kill you either. Again, it is a question of balance. For a variety of reasons independent of this study (obesity, diabetes, etc.) it is a good idea to limit levels of high glycaemic carbs. One does not have to completely eliminate them, but limit consumption , definitely, yes.